You are going through a bad time, so you will feel vulnerable.
Sadly, there is little that you can do to alter things.
If the posts upset, you ignore them. They are probably not meant to hurt, just an expression of their excitement and enjoyment of the holiday. Don't grudge them that bit of happiness.
We have a family member who seems to delight in putting us down, so nearly all of the time, he is ignored, or minimal contact. He has a vastly different set of values to us, so we let him get on with life. We do miss the contact with his wife, who is a blood relative, and that pains us.
But Life is not fair, nor for the cowardly.
Though he is not near, you still have DH. You are seemingly well.Take comfort from that. Look for the positives.