Sounds the same as my ds - he is 7.

The only time he is happy at home is if things are going his way. Or he is playing computer games. The moment we tell him to stop, he is chucking a hissy fit and then going and antagonising his sisters. But he is an angel at everyone else's place!

He told us last night that he didn't want to live here any more because of his sisters and he hates them. Its a jealousy thing here for him though, he has to share us with 4 others and hates it. Too bad for him I suppose, we can't do much about his siblings because I'd rather he live somewhere else than the other kids to be honest lol

so you are definitely not alone in this xx