I don't want to play mario kart with my brother
What bothers you so bad about playing games?
Because he is a cheater
Well that can't be fun!  I hope your brother learns that cheating is wrong.  Maybe some time without having someone to play with will make him realize that.
I'm going to punch him and beat him up.
Refusing to play with a cheater is understandable. I just don't think we should resort to violence because I think that it will make it worse!