I had no time to prepare and was really put on the spot. Here was my reply:
You can believe in whatever you want Zander. Remember how I told you that there are different religions? That some people believe in God, Buddha, Jesus or Allah? And others believe in nothing? Well, it's kinda like that. Some people don't believe in Santa Clause.
Yeah, I know. Not my best work. Now Santa is in the same category as God, but I paniced and that's what I said. I just wasn't ready to squash his imagination and dreams. He's only five!
He seemed to accept my answer though. After listening to my ridiculous speech he said, "Oh, ok. Well, I believe."