How do you advise your children to deal with a 'clingy' friend?

Well, dont force him to go on a play date. The boy will only get more clingy because he thinks your son wants to be friends. I think just tell your son to be nice to the boy, let him be part of things and introduce him to his friends or other people that he knows, maybe then the boy will find new friends. I think you're going about it the right way, as long as the boys feelings arent hurt too much, there isnt really a set answer