Okay, so my problem is thus: My sister-in-law (brother's wife) has been nothing but trouble since she joined the family. Cannot control her unruly children (not my brother's) and smokes around my children whenever she comes over, despite multiple polite requests not to (oldest DS has asthma and youngest DS is 2 months). It's DD twins' 4th birthday party next week and my mother has mentioned it to brother and his wife. I don't want them to attend as the children cannot behave and are always picking on my children whenever they come over. I haven't physically invited anyone from the family except mum, dad and DH's parents and I don't see why they think they have a right to come to the party. They can feel free to come and visit the twins if they wish to but not during the party.