We are only inviting family kids to the wedding, and this BM knows and has no problem with that. She has mentioned things to me before (unrelated to the wedding) about her parents getting annoyed when she asks them to babysit too often or too many days in a row. I was thinking of mentioning to her that if she needs to she could bring her son to the rehearsal, but would that be rude since he is not invited to the wedding?