Check with the holiday company to make sure he hasn't canceled you and the kids, just to be safe.
I recommend not being home tomorrow while he's moving unless you're concerned about him taking things you don't want him to have. Take the kids out. Go visit friends.
I'm not sure I'd wish him happiness - makes it sound too much like a validation that his unhappiness is somehow your fault. (Which it isn't). How about a simple "Be well"? That still shows you wish him well but subtly plants the seed that he might NOT be well.
