What are my Mom's rights? She is of sound mind.

I am writing for my Mother. Her husband, my stepfather, has Dementia. He has become verbally abusive and is starting on physical abuse. She is 83 and on a walker. Recently, she called the police on him and they transported him to the hospital. He was released the next day, due to his Son stating there was nothing wrong with him. My Mother had to go to my Sisters to live because she is afraid of her husband. The Department on Aging was called in and he was found to be incompanient. His daughter is staying with him and they have taken over my Mother's home because they will not put him in a Nursing Home. Now, the Son has filed to take over their finances. My Mother has Medical and Financial Power of Attorney for my Stepfather. She lives on a very fixed income and cannot afford to pay for attorneys. Any suggestions? Would it be better to get a divorce and let his kids handle everything? If so, can she sell the house and get her half out of it?