SIl (aged 34 years) always has a party for herself, she gets lots of presents and thoroughly spoilt by all her family. We buy her present from me and DH (her brother) and our children. She hasn't come to DS's b'day tea (3 weeks ago) all said why or sent a present, card or phoned. I now want to boycott her birthday which is in October. Advise please - thank you.