what is the medical term for his condition?
Also one more thing - the bears. Can you fight them? Or maybe negotiate somehow?
I vote for psychosis with delusional beliefs. Negotiating with bears.. interesting.
If he climed quickly above 2400 m, I'd vote for altitude sickness
. It usually not occur below 2400 m (8000 ft), so probably not in PL. But it can be a serious condition.