In a nutshell I've bollocked my 6 year old for telling his sister (DD, 9) that he wishes she wasn't a part of his life because she interrupted a game he was playing on his tablet (Crossy road) they normally say this kind of thing to each other but DD was really upset by it so I blew my top and told him I would be deleting the game off his tablet which obviously upset him. However DH said that DD had been nit picking at him earlier on and now I'm wondering whether she did provoke that reaction to some extent. I now wonder if I was too harsh as I can hear him crying himself to sleep. He's also had a tough time since starting year 2 as they have been made to do a lot of work with most of his peers now crying when going into school and he's told me it's stressful at the moment. AIBU with my reaction to him by what he said to DD? For context me and DH are only children so don't have the experience of sibling fighting we don't know if this is normal behaviour or not.