I wasn’t comparing myself to a 14 year old but empathising with the amount of pain he must have been in.
I fully understand this worry people have expressed on the thread about the possible pain the boy was in, but since his mum and he didn't get back from the hospital until 'late' (if I've remembered the relevent post from the OP correctly) it sounds as if his being checked over took some time anyway, so grandma rushing over in a flap wouldn't really have helped much, if at all, anyway.
Having broken three bones during the last seven years myself, and having a very low pain threshold, I'm pretty sure that if you keep still the pain is not agonising. Certainly that is my experience. So, again, waiting at school – one presumes they gave him somewhere comfortable to sit and wait – won't have done him any harm.
I think shock actually helps in that regard too.