My stepmom can no longer care for my Dad, yet she won't give me the rights to care for him or get someone to care for him. What can I do?

He can hardly see, has a hard time walking has a pacemaker since 2005 cause of his stroke. He has a hard time getting out what he needs to say. Can not talk like he use to. Has a hard time remembering . Me and my brother are about one hour and a half from our folks, so its going there each weekend to figure out what to do. My stepmom has finally said she would sell there house, but question is don't know if that is going to happen anytime soon. She is being very verbally abusive to my dad and does not care what happens to him at this point. And yes money is an issue. His Social security is not enough to place him in a home. My daughter at this time is taking care of him. But in a couple of weeks will be moving out. My stepmom at this point is having heart issues and has been in and out of the hospital several times. So she is not able to care for him at all. 

We need more details. What are dad's physical/neurological issues? And stepmom's? What is their current living arrangement? How close-by are you (geographically)? Any other sibs/step-sibs in the picture? Is there any uneasiness about money?