My daughter doesn’t visit me very often because my mother is very, very rude to her when she does. My son, who recently got out of the Army and temporary lives in my motor home, has a very difficult time with her. And recently, my other son who drove up over 700 miles to visit me has stayed only 2-days before leaving to stay with his sister. My nephew who she raised and said could temporary stay for a couple of weeks (he is staying with my son in the motorhome), only stayed 1-day before she told him to “get out” and started arguing with everyone. This happens while I'm at work. She is a very, very negative person. My children informed me that they love me, but can’t tolerate their grandmother anymore. My son who drove 700 miles told me that he will not visit again. I will have to visit him instead.
If none of your sibs are willing to care for Mom that tells us all something and you should not be the one to make such a sacrifice
Does Mom have dementia? Other mental health issues? What exactly are her impairments? What is her financial status? How old is she?
Could Mom live in the motorhome and your son move in with you until he gets on his feet?
I'm sorry that all I have are questions, but I think that we need to know a little bit more about this situation before making suggestions.
Off the top of my head, I'd say that the solution is for Mom to leave, but I'd want to know more before offering that as advice.