Make sure that they know how to decock a single shot safely too
Once upon a time there was an eleven or something year old who was hunting with a .410. At the end of the hunt he was told to drop the hammer on the firearm. Proceeded to brace it against his prize possession and dropped the hammer but his thumb slipped and thank God it wasn't a twelve guage.
Never messed with decocking a hammer type shotgun and not sure that I would know how to properly do it. I'd assume that you would hold the hammer back, block it from contacting the firing pin while releasing the trigger and gently ease the hammer down while pointing the muzzle in a safe direction.