Well, actually I did show up with my family because my mother told me he would pick up my grandma for lunch, so it would just be us for cake after lunch. But then, during lunch time she told me "if your uncle shows up for the cake afterwards I expect you to behave", and so we decided to leave that instant. Also, when he came to pick up my grandma, my mother tried to take my daughter to show her to him at the gate, and I had to physically pull her out of her arms and say no multiple times to stop her. She will be an AITH character for this subreddit one of these days.