I was contacted by APS. They are saying the document was fraudulent. What can I do to help?

This really belongs in the hands of a Lawyer now. I suspect that any letter is not a legal document, and especially if she married AFTER such a letter. That would tend to negate a letter written.
It is time to see a Lawyer and take that as final advice. I am sorry. Often when legal documents are not done, and updated correctly, there is no help under the law. Wishing you the very best.

When Kay had given the letter to the hospital she asked them is this legal so they can't do this to my sister anymore the doctor said yes, granted it is not a professional POA.it was notarized I don't know if anyone else was there or not I have no clue to be honest my sister had wrote this letter again several years ago when she went to rehab and she had everything going on we'd all forgot about the letter honestly until my sister Kay had found it looking for something else and came across the letter.she has the hospital if that was you know okay for them for us to take over medical care of my sister I don't care about the financial aspect when my sister ended up in the hospital at that point in her life she didn't have any financial assets only her social security and monthly and with my brother-in-law didn't take for child support and then her house so I really don't care I mean there was no they made this dirty and ugly by making it about money when my sister didn't have any it's not about money it's about her care but for them it's about money and controlling my sister even now at this point we're at my brother in law has absolutely total control and there's nothing in this world that we can do as far as I know they did not only did he accuse her emotionally mentally and physically when she was in her right mind now he gets to do the same exact things now that she's not and still get out and keep everything and keep now he's keeping my nephews from me my younger nephews from me and it's a big mess my oldest nephew Mark through his brother out of the house my other nephew he is a retired Marine and he was told to leave the house he's also not allowed to have contact with his own Brothers and which is extremely wrong they're doing all these things because they have control and it's only about the control and the power for them not for us so if anybody has any suggestions that we could do please let me know know the POA was not legal POA it was just a letter my sister had wrote and in that letter she did mention myself Kay and my nephewmainly because she knew that we would make sure her wishes were taken care of however I don't think that she thought at that moment time that she was still going to be married to the monster that she married. My nephew and his stepfather are the ones that called adult protective services. The adult protective agent immediately kept saying that the document was fraudulent and I asked her how she could say that she said because I know it is I said how if you have physical if you have proof then show me but until then if you call it fraudulent one more time I know my sister and I know that she wrote it at the time I didn't see her write it but I know she did she told me she told my other nephew too that she had wrote the wrote it but I didn't I don't know when she got it notarized right then or later on but I do know that it without investigating it she can't just automatically say it's fraudulent this is less than 24 hours after they had done that against her wishes. The agent continually said that the document was fraudulent it's not a document it's a letter that my sister had wrote that she had gotten notarized at a later time don't know it you know all the specifics I just remember my sister telling me about it that's it however they're trying to make it up into something horrible and sinister when all we want is what's best for my sister we don't want her to suffer you want her to be able to enjoy her grandchildren and if she's not able to do that or be able to walk talk or understand who people are and have 24-hour around the clock that's not what she wanted so I don't know what to do if anyone has any suggestions I think I've answered most everybody's questions of course I talk a lot however if you have any suggestions or any answers please let me know thank you all of you for taking your time to read this and to answer

Thank you all for your responses. unfortunately my situation has not gotten any better. My younger sister Barbara estranged husband have seven children together the oldest four are with someone else and the younger three are with her with her current husband. The oldest son Marc is 25 he has not seen his mother but a couple times in last couple years because of his current girlfriend who is very mentally and physically abusive to my nephew and she told him that he would never see his kids yada yada yada if he kept in contact with his mother so basically quit talking to your mom or you won't have a family anymore my nephew is a big idiot aside from that he stayed with her and only saw my sister a couple times throughout the years matter of fact she didn't even meet her grandson till you know her youngest grandson till he was like a year old that all said the last couple years have been really hard on my sister she wasn't making the best choices and he didn't agree with the things or choices in life however that didn't take away from the prior 42 years of her life that she did make excellent decisions and she was a wonderful mother. however her husband was very mentally emotionally and physically abusive to my sister when she chose to leave him and free herself from that he basically about time she left she was a shell of the person that she used to be she's lost all of her integrity her confidence or self-esteem they robbed her of everything basically as well as you know financially he took all of my sister's money she was in several it was in a car accident had many different back surgeries that did not go welldue to all the pain and that she was having she became addicted to pain medications and it just escalated from there on top of the abuse she was broken and tired when this all happened. She did go seek rehab at one point and then ended up going back to my brother-in-law it lasted a couple days and due to the mental abuse she left again. She then went to go stay with my older sister Kay and she that's when she had some wrote the letter. It wasn't necessarily a power of attorney it was more of a letter that just stating what you know if something was to happen to her because my brother-in-law was stalking her at the time and she was feeling you know emotionally unstable she was in a lot of pain from the back surgeries and going in and out of the hospital and again you know he was very very piece of so she saw is she wrote the letter and it was honestly was just a letter and it stated that you know if something was happening when she passed that she did not want my brother-in-law to stay with the house that she wanted it sold and you know between all the children and mind you this all started shortly after my sister got his papers fixed he was from Mexico on a visa that had expired.when my sister met him he had no financial assets whatsoever everything he owned was in a brown paper bag since being with my sister they both worked my sister got received social security for my for different things and then when she had the accident she received her settlement her workman's comp etc etc however all my sisters money went to buying her house and paying the bills taking care of the financial the family financially while all of his money went to his family in Mexico or whatever he wanted his money was never spent on bills and everything was always in my sister's name and this is before they got married the house that she but was before they were married and in her name only. There is not a problem as far as my sisters condition now until my nephew Mark had said something about a stimulus check before the stimulus was even passed. I was appalled but I didn't care all I cared about was medical well being in my sister and then it was we had to make a decision of taking her off of the breathing & placing trache tube. My sister did not want this and said that to EVERYONE yet they went against Everyone's wishes.

I think it needs one or two witnesses too. Not sure if a notary alone can be a witness. This is why going to a lawyer is important IMO. Like said, the lawyer verifies the person that is assigning POA is of sound mind and not being coerced.

Contact the person who notarized the document. They should be able to verify that she signed it.

A lawyer is not required to make a POA, but it does need to be notarized, so the notary is who you need to contact.

Also agree with Barb's suggestion, but I'm curious as to what the basis is for APS' conclusion.   Is it b/c the document is  not specifically in the format of a POA and was in letter format instead?  

Is this preventing you from making decisions for your sister?  

You wrote "they", so I assume there's more than one agent involved?

I don't know all the details, but I would also consider contacting APS and going  higher up the ladder, advising that the agent in question is not behaving professionally and is making unfounded allegations.   Ask for a different agent, or at least establish that the agent in question is unsatisfactory and won't be allowed access to anyone in your family.   

I honestly don't know if that's been done, but it's what I would do.   And I'd also do some quick research to determine what action can be taken against the agent, especially if she's interfering with critical decisions for your sister's care.

The APS is fully qualified to recognize a "LEGALLY ACCEPTABLE" POA. A letter won't do. This is a form filled out with a Lawyer appointing a person to act for you. You must be competent to be examined by said lawyer to acertain that these are your wishes. Until that time the next of kin will be appointed as guardian or conservator.
Your clearest avenue now, from what I can make out below with other responders filling us in on the situation, would be to see an Elder Law Attorney with all your facts. At least at the end of that rather expensive hour you would understand exactly what you have, whether it is or is not legal and what to do now. I have no idea your sister's condition, nor her capability now to appoint a new POA. If she is able then a Lawyer may attend her in hospital or wherever she is a draw up a POA appointing the person she wishes to act for her. If she is unable to appoint someone it is now too late to have this done, and legally her next of kin will act for her once cleared through social workers and documentation.
I wish you luck. Your Sister's husband is almost certainly in charge here unless you have solid LEGAL documents.

How old is the nephew? - I take it he is your younger sister's son, is he?

So, what we have is:

The youngest sister of three is in hospital. The question is: who is to act for her and make decisions on her behalf while she cannot?

The oldest sister believes that she has medical and financial power of attorney because the youngest sister wrote a notarized letter stating her wish for this to happen. Dallen, were you present when this was done?

The youngest sister's estranged but not divorced husband disputes this, and has referred the matter to Adult Protective Services. APS investigated and have come to the conclusion that the oldest sister does not have valid powers of attorney. This would mean that the default decision-maker would be the youngest sister's husband, or if he is an adult then possibly her son.

This is clearly a complex and emotional situation, which we might understand better if you shared some of the facts that the APS agent is not aware of. But I don't think you can do better than follow BarbBrooklyn's advice.

Meanwhile, how is your sister?

Is this a properly executed POA? Or "just" a notorized letter?

Who contacted APS? The hospital? Estranged husband?

I would start with the Patient Advocate's office at the Hospital. Explain the situation to them as factually as you can.