When my dad was alive, he made life incredibly easy. Begining on Christmas Eve and all through Christmas day, he and step-mom had easy to prepare, eat-as-you-wish-type food ready. When we came, we came. No "must be here at this time" and "need to have the whole family together" drama. The tree was, up, the music was on, the gifts were waiting. Just show up on your own schedule.
And we needed it, since my parents were divorced and my mother lived alone, we had THREE sets of parents to visit. And my in-laws were anal about having the whole fam-damily together in peace and harmony at EXACTLY the time they wanted us to. Usually that was right in the middle of the day, leaving no time on either end for comfortably visiting others.
Fortunately, my mother was just as relaxed about it as my father was, so we just squeezed them in around the monster-in-law's command performances. It never caused fighting between DH and myself, since it drove him as crazy as it drove me.