I've done all of these - last week I was ready to pitch my iron and head to the store for a new one, so...
When all else fails, make sure it's plugged in!
And your son is not the only one who has issues checking hot stuff with his hands, my neighbors dd has on more than one occasion watched me take a pan out of the oven with a hot pad - and ask me "is it hot?" as she puts her hands on it!