Ultimately, time was what Alex needed. By Christmas that year he was fully back to normal and Claire nearly cried from relief. He had been carrying that weight on his shoulders for so long and there wasn't much she could do to carry it with him.
He still didn't want to spend major holidays with the Barbers because he was used to doing them with the Wagners. They did end up going to their house for Christmas Eve though instead of doing their own thing like usual.
The energy of having a big group of people together was rather similar to the one they were used to on holidays after having the chance to get to know the Barbers better. Claire was sure that the more time they spent together, the more comfortable everyone would continue to be.
You could never have too many people that cared about you. Having more extended family wasn't a problem at all.