Op, my DB and I have always had a difficult relationship, he was the golden child, he was never very nice to me and certain things came to light not long before mum died which made me hate him. I had always had as minimal contact as possible with him and that reduced even further (text every few months) after she died and the estate settled.
Earlier this year he suffered the unimaginable tragedy of losing his only child suddenly. As neither he nor his wife had any other close relatives in UK (she is from abroad, does have lots of friends in UK) I rallied to support them in immediate aftermath and at funeral. I couldn't not do it,
whatever had gone before. Some relatives said I was amazing, no, I was just doing what felt right at the time, for me as well as them.
We do have more contact currently, but most of it is him texting rants about people (not me now, he knows I would go NC but the tragedy doesnt seem to have changed him at all.)
I dont ever think about the sibling relationship we dont have, I just remember all the nasty things he has done and said over the years.
We never saw him at xmas anyway, we dont live close so our Christmases were always spent alternating with parents when both sets alive. Now mine have died, it is one year with inlaws, the next just the four of us. As a pp said, I am looking forward to a chilled time this year with just us 4. DD is working in retail this year, so not much time off, so what time we do have will be precious.
I have no idea whether I will contact DB on xmas day. Maybe just a 'thinking of you' text. He stopped cards and presents years ago, part of his childish attempt at manipulation. His wife and DD sometimes went to see her family abroad, so they didn't always have xmas together anyway. I think his wife may do that next year, she is supposedly taking ashes abroad, which will make his Christmas harder. But - my DC hate him with a vengeance, which makes it easier for me detach, as they are my No 1 priority.