Family issue (tradition, blood, divorce, Christ, gathering)

[Quoth The Raven]

First things first...you've said you get together 'around' Christmas, which I would take to mean not Christmas Day as such. So that being the case, he isn't asking everyone to abandon their spouses on Christmas Day and dance attendance to his whims. He's excluding his own spouse as well, which I take to mean it isn't personal, but there is obviously - to my mind - something important that involves your father and sibling and needs to be discussed. My first thought was,'Maybe he needs to tell you all he's dying and he wants to do it without everyone else around.' Yeah, crappy timing, but if you all don't get together other than around Christmas (even though you live like 10 minutes away from each other, for pete's sake ), when else is he going to do it? Unless he goes and sees you all individually, and then he has to go through the whole thing multiple times.
As everyone else has said, ask if there is something going on that requires the non attendance of the spouses, and suggest that if that is the case, do that before and then celebrate Christmas as you normally would. Obviously at this stage it may be a little late in the game for that, but it seems odd that after 10 years he would suddenly disrupt the status quo for no reason.

[Todd]

I did go ahead and talk to him about this. Well, turns out his wifes family was in town, so since his wife couldn't make it since she was spending time with them, he thought it would be best to not have spouses at all. He also said he just wanted to get together with just me and my sister, since we haven't been together (just us three) for a long time. Lady_Lazarus, your assumption was correct about "Christmas Time". I usually get together with him two days before Christmas, then I get together with my Mom on Christmas eve, and my in-laws on Christmas day.

Anyway, we had an enjoyable time. I still wish we could get together more often than once or twice a year, but usually his work or my work gets in the way.

Thanks for all the advice.