Definitely a mental breakdown. Poor guy. My fiance had a psychotic break after a history of mental illness, compounded by drug use. It looks like Bryce might have been either psychotic or suicidal or both. I hope he found peace somehow, but I think he ultimately killed himself. Or ran off into the woods and died of exposure, maybe his body was eaten by animals so that’s why he hasn’t been found. The fact he gave away all these items indicates that he wasn’t planning on coming back. And that letter to his friend. “You saved my soul”. Not “you saved my life”, which would be a more normal thing to say.