my son is 8 years old and has come a long way when it comes to interacting with others. he is very social with his siblings and also has no problem making friends when out. the problems we deal with are when things don't go his way. he gets upset and that's when things get difficult. he "overreacts" when someone is not playing the way he wants them to. for example, he is very generous in allowing others to play his video games but he has a hidden agenda..............he wants them to play the exact way he would. he then has a mini meltdown and you can picture the rest.
the best thing to do is get the other children to take interest in things you know your special needs son will play with and often things fall into place.