How the boys celebrate Christmas would depend on their circumstances at the time -- where they are, who they are with. If they were at Devil's Hole with the gang, I doubt there would be much celebration except maybe with alcohol. If they were just with each other, I think they'd acknowledge it. get each other a gift, have a drink of good booze, and that would be it. If they were with people who observed, I think they would be polite and observe as well. I can't see them going to church on their own volition, but if they were with someone who told them, be ready at such and such a time, and if it was easier to say yes instead of say no, they would go.
I don't think the boys have any deep religious feeling other than what they may have been taught as children, and what they get from the general culture in which they lived.
To sum up, the boys' observation of Christmas would be a response to whichever situation they found themselves in at the time.
Personally, I don't celebrate Christmas. It's just a slow time where I am very bored. There are a few good parties to attend, and that's a lot of fun. But the holidays are a time to do lots of cleaning and watch lots of videos. I'm always relieved when they're over and normal life can resume.
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