The cast of this particular Christmas Panto are all reading from their own scripts.
We seem to have a Sad Sack, not one but two Selfish Siblings, and a Pushover. The poor Grinch is merely an understudy.
You could have put an end to this non-drama immediately by not involving your DH., and announcing that Christmas would take place at yours, as usual, Siblings welcome but you’ll be happy whatever they decide……though the presence of the Sad Sack is totally non-negotiable. Why should DH be involved and have to adapt your Christmas because SSack may (predictably) choose to have a rubbish Christmas? Your kids are more than old enough to do their thing and not aim to spoil yours, and as it’s been suggested already, they can organise their own Yuletide shindig and get Sad Sack involved/take Christmas to him/arrange a completely different event/leave him to sleep etc.,
Who cares? Well, you it seems and far too much - as The Pushover! Bet you’re a very nice person, kind-hearted to a fault, and a people pleaser.
Well, this is one occasion where you only need to please the chap you’re with. Indulge him, not let everyone hold him responsible because you couldn’t immediately hold the line. Everyone will benefit and important lessons will be learned.
Make sure you and your non-Grinch have a super time….and please remember - your firm decision now will help everyone else to make sensible arrangements.