I'm new and have only been here a week. This is a live in on call 24/7 situation for me. This 90 year old man has his poor wife, who has already injured her back trying to lift him prior to my arrival, hopping at his every petty demand. His three daughters are in and out, acknowledge the problem and avoid dealing with it in their own ways. Help?
People with dementia are sometimes hostile and difficult to control and protect from themselves, but it has to be done. It sounds like the man's children are trying to avoid making that decision. His doctor may also be of some help, but if no one has POA, it may be difficult to act on the man's behalf if he resist.
However, if he begins to think that he can treat you like a slave then that needs to be nipped in the bud. Don't wait for his family to step in, they're just relieved that you're there now and the major heat is off of them. I hope you have an agency you can turn to.