Growing up my mother never let it slip once that Santa was not real. Even as adults she would never accept a thank you for something that was "from" Santa; I admire that.
I was reading recently a blog post from by a woman who's son still believes in Santa Clause. Like my step-son, her son has Aspergers. This mother's dilemma was about how to tell her son gently that Santa was not real. Her fear was that if he still admitted his belief in Santa that he would be ostracised and picked on at school and by his peers. The sad truth is, most ten year old's these days do NOT believe in the great Santa Clause; so I can empathise with her dilemma.
Kids with Aspergers really don't understand sarcasm, and have a hard time discerning between truth and fiction. If my teenager didn't "spell it out" for my step-son, then he'd still probably believe too. For instance, if I played it serious enough and told my step-son that as a child I cut my hand off (using a sharp knife that I shouldn't have been using) and that my mother glued it on; he might actually look for the seam in my wrist, or ask me what type of glue she used. If I told him that I was over the moon that I received a nice compliment from someone, he might spend some time wondering how the heck I got up high enough to be over the moon... but I digress...
Anyways..so it got me to thinking..as it always does; why tell him Santa is not real at all? Santa after all really is about a feeling in your heart, so why instead don't you let him just believe. Why not just agree with him that "yes people are crazy to not believe", and explain to him that it's just a fact of life that a lot of people don't, and so maybe he should just keep that belief in his heart... or at least just keep it at home..with his family... (who of course all still believe)? Even he will eventually find out about the Santa myth, but he'll find out in his own time.
It may be silly, but really it's a harmless thing to believe in; and it's a belief that brings a lot of joy and excitement... something to look forward to.
My two eldest children do not believe; but like my mom, I don't take credit for Santa's gifts, we don't admit to eating Santa's cookies, or drinking his eggnog, and I still use the "Santa is watching you" (Even when you're in the tub or using the bathroom..because I'm crazy like that)... and really what's the harm?