It takes a little snow

Christmas is tough for Norrin. I know he likes it - the presents and candy and Santa. All of those things he can see - they are concrete things. But the idea of Christmas, the feeling and excitement that comes with the anticipation of Christmas. I know he doesn't get it. Christmas is full of abstract concepts that are so complex for his mind to grasp. It's religion, the birth of Christ, faith. How do you explain faith to a child with Autism?