My sister stole almost $90,000.00 from my Dad's checking account. What do I do?

Yes, I said $90,000.00, more than half of his life savings. My sister was supposed to be taking care of paying my father's bills and other expenses and picking up his mail for him after he had two mild strokes two years ago, that left him partially blind. This past November, he asked me if I could go to the bank with him and have them tell him what was in his account. I asked about the bank statement he should be getting every month. He said my sister told him they didn't send him one anymore. I called BS to this, stating that even though I hardly ever do any activity on my one account, I still get a statement every month. So, I took him to the bank and he got a print out. Well, to find out, she had them him get a debit card, which she took possession of instantly. He never even physically touched the card. To find out, as soon as she activated it, she was draining money out EVERY DAY! Not only would she get out the max cash that was allowed, she shopped with it all over the place. (In one day, she used it at three different Wal- Marts!) In one day, she spent more than what his Social Security check is for one month. She wasn't even paying his utilities on time, so he was paying unnecessary late charges. On top of that, she has his Medicaid so screwed up I don't know where to begin with that. The real kicker was the lettesr I got today in his bundle of mail. She never paid his taxes last year, so now they are threatening to take his house. And a doctor is threatening to have a lien put on his house, because she never paid those bills either. (She was asked multiple times by myself and my father if she did, which she said she did.) When I found all of this out, my brother and I confronted her. She had a choice, either counseling or jail. Plus, she still had to help take care of him and start paying the money back. If she didn't agree, or failed to hold up her end, we would press charges. She claims she went to one counseling appointment so far, but has yet to pay him even a dime of his money back. And now, she barely even helps take care of him anymore. I reminded her that there is still time for my brother and I to press charges against her, also reminding her that she would be charged with Class A felonies and a federal charge for mail fraud. (My father asked her repeatedly to bring his mail to him, which she did not.) I made an appointment with a lawyer to become his Power of Attorney, went to the bank and made sure she couldn't get any information about his accounts, and went to the Post Office and put a stop to her picking up his mail. Is there anything else I can do? Thank you for letting me vent. I am so upset and depressed over this, I ended up getting shingles on my face. Any advice would be deeply appreciated.