S.S.
She sounds HORRIBLE! First of all, I would stop trying to let her have a relationship with your children. I would just tell her that when she wants to see them, she can call you. She is receiving too much control when you ask her over and over. I would also tell her this in front of other people so that she can't say that you are keeping your grandchildren away from her. If she doesn't call, then it is her loss, she will miss out on the joys of being an involved grandparent. I would also be worried about what she might say to your children, if she is that nasty to your husband about his conversion to Judaism, what is she going to say around the kids? I would make it very clear to her that if (actually, it might work better if it came from your husband) that any negative speech about Judaism will not be tolerated and if she can't comply, she can't be around the kids.