their grip tends not to really change while sleeping, so falling off something steady is unlikely. i wouldn't be surprised if a cham would fall off a leaf though
It all depends on the position he falls asleep in. I saw a post recently about a chameleon falling asleep hanging onto the roof with his two back legs. In that situation, yes, I can imagine it falling. However, if they fall asleep normally on a branch, I don't think it would happen often if at all.
My veiled slips down when he sleeps. I often wake up to find his back legs dangling while his front legs are still clinging to the leaf. He's fast asleep of course. So he's never actually fallen, but gotten close!
Chameleons may fall on purpose if spooked by a predator. They are designed to take a fall. Its the easy way out There are risks, just like everything else though.
And remember, even if he did fall chances are he wouldn't get hurt unless he had severe MBD or some other problem. Chams fall accidentally or let themselves fall out of rainforest trees, hit the ground many feet below, get up and walk away without a scratch.
I wonder if they'd puff up for shock absorption even when asleep? Probably would, nothing to really worry about anyway, 'cos he is very unlikely to fall...........
As mentioned, they have evolved the tactic of just dropping to evade predators if they need to and they have cartilage instead of bones for parts of their ribs, so natural shock absorbers is just part of how they work. I don't think they are like cats and always land right though, I guess it wouldn't work if he lands on his face.......lol, don't worry though, it really is fine