Quoting .Twat.Waffle.:" Wow.... Do you have day every so often where you wish someone would just get hit by a bus? Yeah... one ... [snip!] ... have a lot of trouble with my blood pressure dropping. If I passed out, fell, and hit my head... no one would find me for days."
Dang, I had trouble taking the time to read that. Your avi was fascinating me. I mean, that is really entertaining!
You're being completely reasonable. If he said he could not make it, then it's fine to make other plans. Sounds like he is being a total douche to me.
However, with that being said, could both of them go? I mean, bring your sister in law along for the support, but then tell him that he can come as well. That way he has no excuse to be a dick about the whole thing, and it will actually come down to whether or not he wants to be there.