I've picked up on the fact that he may experience a certain misery within his family, like they're not giving him enough space, so it could be an ISTP trait specifically in a situation where they aren't properly "left alone.
What I've realized is everyone has things in their life that are difficult for them. So with anything practical, where my innate ability to do well is apparently enviable, feeling like I don't have enough space with family sometimes is my "algebra class".
The things where other people are thinking "I can't do this!" that I find so easy, compared to things that I feel like I can't do like remaining in a social situation where I don't feel I have very much space is like 99 to 1... so I do the best I can, I got nothing to complain about.