Revealing yourself to be an atheist varies from person to person.
For some it is the wrenching of the trenchcoat to reveal (Steady on!) to all and sundry that the person inside is an atheist. For others it’s a gradual process of simply stopping participation in religion.
I saw a letter of a desperate mother who fears her son’s atheism means that Christmas cannot be celebrated and I will say this.
When Diwali comes around in India despite it being a Hindu festival, Muslims and Christians come play with fireworks and put on new clothes and even put out the lamps that give the festival it’s name. When Holi comes there is no restriction on who may throw colours.
You don’t have to pray to enjoy the festival of Christmas. In our modern world the religion has made way for something that matters more.
Do you think Christmas Dinner is ruined because one person at that table does not believe in Jesus or in the tastiness of Brussel Sprouts? No. The Dinner simply moves past those choices. The son who doesn’t believe in Christ simply sits out the prayer portion and contrary to all belief the mere act of praying around an atheist does not move us to violent rage. We respect your right to pray just as we expect you to respect our right to not pray. The problem arises when you FORCE someone to pray.
You don’t force people to eat their sprouts, not unless you want an argument.
The presents? You don’t need to be religious to give or get gifts.
The social interaction? I find that Christmas arguments happen just fine without Jesus since NONE of my Christmases ever had Jesus involved in it.
Your son is lucky to have a mother who wishes to try and include him rather than fear his lack of faith and that’s what counts. Christmas is also a time of family, sharing and having fun.
You may see atheists argue against Christmas displays on public land and that’s because there is a rule in the USA that states that Public Land must be secular and invariably Christmas on such land is heavily Christianised. In effect it is forcing all and sundry to eat their Brussels Sprouts, even if they don’t like it.
Remembering that will help you understand that atheists can enjoy Christmas and so can Hindus and Muslims in the west by taking the secular ideas of Christmas and holding to those while not participating in the religious ones.