This is a tough question. I might try talking to his teacher, in private of course, to see if there's a deeper issue than that. I know he's only 5 so it may not be likely he's covering up deeper feelings, but you never know...maybe there's more to the story. Just mention to her/him that he's hesitant to go to this child's party and do they get along at school, etc. Maybe that can help you make your decision. Otherwise, I'm confilicted as to what i would do, but I would probably send my kid to the party, but honestly, I just don't know. That is a tough one!