How do I handle my sister's mishandling of our father's income?

Years ago my sister took over our father's financial responsibilities as he began finding it a little confusing and because she told him she thought it was time she took over. At the time she had him sign several documents and rather than him reading each of them, she verbally told him what each one was and told him to just "sign and date it here". He had no reason to doubt her so he did just that. He was with the understanding that he was signing permission letters; release forms; for banks, utility company's and the sort so she could conduct his business for him. What she didn't tell him was that in reality, he was signing a "General POA" and a "Financial POA" (each are really about the same). The financial POA document had a line by line itemization of different powers he was giving her permission for. He had no reason to doubt her so as directed he initialed each paragraph. Once I was shown these documents, I have been trying to tell Dad what was really taking place. He ignored me for about 18 months until I was able to get a copy of the document and go over it line by line, showing him what he had given her the power to do. And as time went on I have been trying to convince him that when he does pass, she will be getting everything. He argued stating he wanted everything split evenly between us and that is what his will states.
Well, trying to get ANY kind of paperwork regarding Dad's financials and his Will has been like pulling teeth.
Two years ago when asked for the Will I was given a "paper" called "FIVE Wishes".
Six months ago in a phone conversation I asked for a copy of Dad's Will and any and all statements for the past 6 months from each of Dad's bank, credit union, credit card, loan or any other institution he does business with. I was yelled at and told that I was accusing her of stealing. I was asked "What do you expect to find?" As I calmly explained that Dad AND I want to see where his money is and what it is being used for. It took 3 months to receive any statements. I received statements from one bank and one credit card company.

In 2014 my parents were placed in an assisted living (AL) facility. My sister sold all the appliances in their manufactured home to the person who was moving in beginning April, 2014. It was said this money was needed for deposits. Because Dad served in the Korean War and is a Veteran, he receives benefits from the VA for his (and Mom's) living arrangements. All paperwork was handed over in a timely manner. Because it does take time to process, a $25,000 loan was taken out to cover expenses until the VA took over payments for the assisted living facility.
At present date, Dad's income since March, 2014 is approximately $108,935.00. After receiving all statements and learning a few things, when I asked how much is in Dad's account(s). I was told he has about $4,000.
It is my belief that his money has been used for my sister's personal gain. I will stop at nothing to get back what is rightfully his (and yes, mine in the end). She gives him NO cash to go out to Walmart with the facilities outings or to eat, etc.
Does anyone have any advise for me? I am running out of time quickly and am at a loss. I am living on disability and cannot afford a lawyer for Dad.
PLEASE! If ANYONE CAN HELP IN ANY WAY, PLEASE DO, WE ARE DESPERATE AT THIS POINT!

I know this is VERY long, and I apologize for that, but thank you for reading if you've gotten this far!

God Bless,
Lynnisshining!

Paper Named: The Personal Representative's Role; attachment to "Will of .....Paragraph named "Names mentioned in Will" Has my 1st daughter's name appearing as "Grandchild" AND "Beneficiary" however, the Will lists her as a Grandchild only; it is my sister and I who are listed as the beneficiaries. Also, my name in the Will includes a middle initial; I have NO middle name. Will this cause problems down the road...

Will: Paragraph named No Contest Provision - If any beneficiary under this will contests this will or any of it's provisions, any share or interest in my estate given to the contesting beneficiary under this will is revoked and shall be disposed of as if that contesting beneficiary had not survived me.
Then it states if any provision of this will is held invalid, that shall not affect other provisions......

Does this make any sense to anyone out there that is reading this?