I never know what to do when I get these things. I could make him go, and we could hang out for a while, and he would be miserable but maybe he might have some fun in the end? So, do we go in the off chance that he decides he doesn't actually hate it? Or, do we go because we were invited and that's what you're supposed to do? Or, do we go because at some point the invitations are going to stop coming and we might as well go now while we have the chance?
No, of course, the answer is no, we're not going to go, because he doesn't want to go and I'm not going to make him. Maybe if I were a better teacher I could turn it into a learning experience for him, but as I've said before, that's just not where my skills are. This is that thing I'm constantly bumping up again, though: my internal conflict about what he's "supposed" to be like and how he really is. My instincts always tell me to let him be himself, in this case that would mean not going; but my societally-implanted fear tells me that we should go because that's what the normals would do. Then there's that other part of me that berates myself for not being better at this, I should be able to make this a teachable moment for him, but I just can't/don't know how.
So, as is now my custom, I will make an excuse about how we're busy that day (we're not) and thank the parents profusely for the invitation. I guess I can take heart in the fact that one day the invitations will stop and I won't have this internal struggle to deal with anymore. Sigh.