He is an abuser with a violent temper. He is a man who gets physically violent. He also cannot control himself. No, don't spend any time with him. No, do not let your kids be around him. Keep them away from him from now on...for their own safety. I would be very worried about my mom if I were you. His explosive temper will come out when she does something that annoys him as well. You are not putting your mom in the middle. She can choose to not be with him. She can choose to visit her grandkids without him. She can choose to come to your house without him. She CHOSE an abusive man...she has consequences for that. You should not feel guilty. You should encourage her to leave him though. I don't think it's safe to live with him.