Sounds like he needs to be in a home. Get him in an assisted living home and your mom can visit when she feels like it. Obviously, what's done is done. but it sounds like his behavior started before his current medical condition and should have been dealt with a long time ago. At some point you have to do what's right for your mom.
It's a tough situation that we dealt with somewhat many years ago. My Dad and I had to come to an understanding that me as an adult and my family would not tolerate poor behavior.
