I took the coward's way out.
I sent him email telling him - since we dont get to talk much - that there was a party, that I had told them he couldnt make it due to work and that even though work had cleared up he needed to be here to babysit since I had not made other arrangements. I added that I was sure this was okay with him since he didnt enjoy my family parties.
Well, I checked my email periodically but no response. When he got home, I asked him about the flight info for our vacation in Oct (I sent that at the same time.) He had seen that one. But then I asked if he got the party one.
"No. Saw it but didnt read it."
So much for that. I just repeated what was in the email. He said he would want to "wish her" as they say in his family. But he agreed he doesnt enjoy those parties.
I did tell him I was glad he couldnt come. He asked why (of course - or maybe not "of course".) I told him because he spends all the parties just sitting in one place, staring at the floor or chair, until someone comes up and talks to him out of pure pity. He didnt respond.
If he has time to think about it, I'm sure something will come up this morning about it.