I would also consider making a different holiday plan all together, maybe make some plans at your house. Invite your family to come by after they do other things, state very calmly and clearly that you do not want his alcoholism to throw a shadow on your day.
I do not feel that is bailing him out. It almost seems like, if everyone goes to his house and plays jolly, then he is being enabled. Surely, no one wantes to have a crappy holiday, so...they are bound to pick up the pieces for him.
Why not just boycott? Make your own damn plans, and if any of them ask why/what, just be CALM and direct. I do not want my holiday to be stressed because of someone else who wont address his disease.
I choose to have a happy holiday.