I agree with chatty.

Have your husband "pave" the way. If this woman is mentally unbalanced, there is no reasoning with her. He should visit her and the children for an afternoon. Maybe he could bring her some flowers. No further words are necessary.

Then, the next visit, join your husband, and simply act like nothing happened. I know, it's a matter of swallowing your own pride, but you win in the end when you get to see your grandchildren again.

I can truly sympathise with you Eagle. Nothing can get my goat like, being treated unjustly and uncalled for. I know it takes a lot of self control to "take" it. Those children need you, if their mother is unbalanced and angry. Take this as your mission, to show the grandchildren there are other way to cope and handle conflicts. Your quiet and calm way will automatically draw them to you.

Sending you a big big hug.
_________________________
A friend is a gift you give yourself.
-- Robert Louis Stevenson