Can a daughter get POA over her Mom with dementia when her Dad is POA through an old living will?

How advanced in your mom's dementia? I'm asking because if it is just the beginnings, or mild, then the elder law attorney would interview her privately to assess whether she can comprehend what assigning a new PoA would do. It has less to do with memory and more with understanding. If she's not that advanced then consider taking just her to an appointment with a lawyer. Otherwise, it will need to be guardianship.

There are ways to have a power of attorney overturned if it is being abused or if the person given power of attorney is not able to exercise it properly. You still wouldn't get POA, because only your mother could have given you that and it seems she no longer can, but it would take control of her money and decisions about her care out of your father's hands.

You can call APS and get advice from them, you know, without necessarily making complaints or accusations. Or you could go to a lawyer and get advice on her behalf that way. At the moment her wishes and her best interests are being ignored, which is plenty to go on without blaming your father for anything worse.

You say your mother wants to go in a care home - okay, but why does she? Are you sure she isn't agreeing with you when she talks to you, but agreeing with your Dad when she talks to him?

Your father has no choice but to pay for it.
If you live with them, you will need to move out so he understands that.
Once your father, who I assume is NOT demented, puts your Mom in a nursing home she will have to spend down her share of their money (an elder law attorney can help them divide assets) before she can get medicaid.
Under no circumstances can you "get her money.
As long as you are not POA, and you are NOT, then it is up to your Mom and your Dad what they do.
You should leave and make your own life, and let them to their own decisions while they are competent to make them.
If your father is not competent then you can apply for guardianship, which is not cheap to do if either of them fights it, and which, if Dad is even "somewhat" competent, is unlikely to be given to you over the husband.
Currently, by living with them and caring for them you are enabling them to do it this way.
What your Mom "wants" if she is descended already into dementia will not be considered, but the ability of her spouse to care for her may be.

Lizadiane, only your Mom can assign a Power of Attorney, and from what you have written, sadly your Mom can not longer do that due to her stage of dementia. But bravo, she still has common sense to know it is time for a village to help in her care.

If possible, make an appointment with an Elder Law Attorney to see what are your options and what can be best for your Mom.

Ask your Dad what if something happened to you and you could no longer take care of your Mom and Dad, then what? Would Dad be able to take care of your Mom on his own?

In my case, my Dad asked me to retire from my career of which I had worked too long and hard to maintain. I asked Dad if he had quit work to care for his parents. And did Mom move back to be nearer to her parents to take care of them? Dad never asked me again.

I know it is hard to set boundaries. Do I hurt my parent's feelings when I say "no" or do I just follow through even though I knew my parents could afford to hire someone to do the work.

Mum has to be competent to assign you POA. Depending on her level of dementia, she might be able to revoke the old POA, but if it advanced, then that ship has sailed.

You could apply for guardianship, if you can prove that Dad is not acting in Mum's best interest, but that is a long and expensive route.

Divorce as an option? She may not be considered to have the capacity to enter into a divorce.

So what are your next steps? You need to talk to an elder care attorney. They will be versed in the laws in your jurisdiction and be able to give you guidance.

You also need to be prepared to move out.