Family squabble - Father is acting rude still.?

My father's last words to me were very rude. He said cussing "F u, F all of you and from now on take care of you own GD kids and leave me the F out of it!" We (my husband and I, 2 kids) moved out of this temporary housing arrangement within a week because of the tension. We had no place to go and stayed with family over the holiday then rented a house. My mother keeps asking to take the kids places and I have not allowed them to go with her alone without me or my husband in fear that she will take them back to her house where my hostile father lives. This feud has been going on for over one year now and my father has still not spoken to me or my husband. We live very close to them which makes this even more difficult. I don't trust my mother....I don't want to hurt her feelings but she has stood by him through this and likes to pretend that everything is okay. The tension between the 4 of us is so thick you can cut it like a knife. I pray for him, he is hateful and now in my eyes unpredictable. How do I tell my mother that I do not trust her to not say something about my father to try to smooth things over to the kids or bad mouth me or my husband in front of my kids. My husband and I have gone to extreme lengths to keep the kids out of this feud. The kids don't know much about this family feud at ages 7 & 9yrs except that their papa is upset at Mom and Dad and that we should just pray that Papa will be a happy person again. I don't trust that my mom will not meet with my father with my kids, knowing that is against my wishes. That is why I have not allowed her to take the kids anywhere alone. I am now forced with the decision to tell her something. She keeps asking to take them somewhere and I have said she is always welcome to come to our house and play with her grand kids. Any suggestions?