I think my brother and his wife are stealing my father's money. How can I get Power of Attorney for my father to prevent this?

I have the same problem. My brother has always been a con artist. He even stole checks when he worked at a funeral home. When the clients went to bury their spouse the gravesite wasn't purchased because he had pocketed the money. My 80 year old parents have ALWAYS been in denial about him and I don't know what to do. They always bail him out and make excuses for him. Now he has a women and two kids living rent free in their only rental house. She has a police record for stealing and is 32 years old. He said she would keep the house clean while he showed the home to potential buyers. I went to Sarasota for the weekend and the house is completely overgrown and unkept. I can't believe the girl with the police record and him work in Real Estate and FLorida licensed them. My brother even changed his name. How can I protect my parents from losing everything and becoming indigent. My friends tell me its their own fault and to stay out of it.