My son is the same Hun when he gets in from school I give him an hour to chill and relax in his own space as its abit to much being around children allay then he gets home and my 2 year old son won't leave him alone but he don't mind it so much now as he has his chill out hour which re chargers him I guess. My son never used to play with children or like anyone in his space. Maybe trying to get them involved in playing games like roll the ball to each other and other turn taking games he might get used to the idea of sharing and won't mind it so much when his brother is in his space x

Ok I will try that. Today surprisingly they havent been too bad. They have been playing together for a while.