As I said earlier, it's not all about me. I wouldn't have allowed my DH to ban my parents from our home, if they didn't get along. I'm not going to ban his. Our feelings on things like this may come down to the way we were raised. I was raised by parents who believed in family first. That will never change for me. I can't imagine anything that would make me give up on my family.
As for the way she treats DS & me, she takes constant shots at me, every time we're out of DH's earshot. He used to go out with his Dad to talk & leave me with his Mom. Over the years, we learned he couldn't do that. She's on her best behavior as long as he's there, so I spend as little solo time with her as possible. A few years ago, he finally decided he'd had enough & had a serious conversation with her about the way she treats DS & me. She's been a bit better, but she still slips up at times. At least, it's an improvement. She's not nearly as bad to DS. She knows I wouldn't put up with her treating him the way she treats me. She's just generally apathetic toward him. He could be anybody's grandson as far as she's concerned. Of course, that hurt him, when he was young. After FIL passed away, she started trying to develop some type of relationship with him. Sadly, he's now an adult & it's too late for that. He still visits her & likes the idea of her finally being a grandmother, but he'll never have a bond with her. To me, that's the saddest part of the whole situation. I'm not sure why she changed toward DS, after FIL died. FIL wasn't the problem. He was a great FIL & grandfather.