My Pap refused to believe that anyone ever set foot on the moon.
I find fossilized trilobites here in PA. Maybe I should invite William to join me on a dig. Trilobites were the first creatures known to have eyes. The ones found near me are 350 million years old. That means they were already fossils in the ground when dinosaurs came around.
He isn't hurting anyone with his beliefs but this just sounds like a case of refusing to listen to evidence, or extreme faith. As long as he keeps playing well I don't care.