In really fed up of my sons behaviour. He is constantly being horrible to his sister to the point I would call it bullying. He is so mean and argumentative and causing constant arguments. I was looking forward to the holidays but now I don't know how I'm going to cope with him arguing and fighting all summer and dreading another 5 weeks of this. I posted about it on another group but was told it was normal and all siblings fight but I don't think to this extent. It's just making me miserable it's all day long. He is 11. Anyone been in this situation?