Why did she need to ask "your" daughters friends things about her? Is there a restraining order? I can understand her still wanting to know what her daughter is doing and still wanting to be a part of her life. That is really sad. Not to diminish at all what the child is going through. But, if the mom was making an effort and reaching out, why is she not allowed to have a relationship with her daughter.
I'm great friends with my ex-sil. I've known her since she was 16. Yes, her brother and I had a bad divorce, with plenty of blame to go around. But, she and I found a way to agree to disagree about the divorce and still be family to each other. She always tells me Happy Birthday. We give each other gifts at Christmas. So far, it hasn't come between her and any new woman in his life. I don't expect her to divide loyalties or anything. But, our relationship is seperate from my relationship with her brother. We have our own bond that has nothing at all to do with him. Could it be possible that these 2 are the saem way? Grew up together, and have a history together that doesn't revolve around him, and therefore is no threat to you?