I'm guessing it's the whole social expectation of it. If it'd been in soft play he'd have jumped at the chance. It's not and he knows there'll be food and games and expectations. In a way i'm quite pleased. He can tell me that he doesn't want to go instead of us turning up and having a horrible time. I don't have to go to a party when i'd rather be doing something else (we all have that feeling at times right) and his friend will have a lovely party anyway.
I told his mum we're busy that day. I also said that Big Man would rather not go, it's nothing personal, he just can't really handle it yet. I'd prepared myself for awkward conversation. She was lovely and understanding. Hopefully one day we'll manage a party but right now none of the kids are bothered by who does or doesn't go and that. I can't force them either, i can't force him to enjoy himself, i can't force people to be friends with him or understand him. I can make people more aware so that's the aim i guess.
Why do us adults make such a big deal out of things that kids just don't? Maybe if we didn't have such social expectations, weren't easily offended, didn't analyse every conversation (i'm guilty of that!) we'd have it much easier than we let ourselves believe.