The documentary is not introducing him as an engineer with great education. He is a dude who lost family as young and at some point decided to live alone in forrest (I guess he has some pension due to amount of stuff he clearly bought).

There are many fundamental decisions he could have done differently ... but that sort of person won't decide to live like this in the first place.

Living in the forrest does not have to imply great wisdom in everything. Sometimes it is just poverty and being a social issue.