Nigel. I will try to minimise the frothing, but it gets harder every time another needless accident sends a bunch of innocent people off for an early bath. Helicopters are great fun and hugely sociable machines and I absolutely get why PAX love them so much. However the pilots behind these kinds of terrible events need protection from their own sense of immortality.
The best advice I would offer your son is stick a tent, sleeping bag, some emergency rations and a good book in the baggage hold. Landing off piste knowing you have a portable home is a great motivator. Many press on dogged by the thought of a cold lonely night practising their survival skills is their only option.
Good luck to your son and keep him safe!