Luckily unhurt but obviously it could have been much worse. We thought he'd gone to sleep but he was messing about leaning over the side and fell. I've moved the mattress to the floor and said we will talk about it tomorrow. AIBU to say he has to go back to a lower bed for now. I don't think he'd do it again, but I didn't think he'd do it in the first place. Husband thinks I'm over reacting but I don't want to take any chances and also think there should be consequences for dangerous behaviour.