FWIW, he's autistic. That will help frame everything when analyzing how he chooses to live, interacts with others, approaches his passion, perceived selfishness, etc. That can also impact fear, or lack thereof.
Ex-boss of mine has mild autism (once called Asperger's). Among other interesting things, it makes him process fear differently.
I've seen him do dangerous things for the job that are totally optional (and not worth it at all) because he becomes fixated on accomplishing the exact thing he wants to do and in the exact way he likes to do it and everything else fades away. He doesn't even register that what he is doing is dangerous or that others would probably make different choices. Nice guy, but this made him difficult to work with.
For instance, standing in between 2 tied up, aggressive dogs both trying to break their chain to bite him a few feet away simply because he liked the angle of a photograph a little more in that spot. But we could have also taken the photo from farther away and then digitally zoomed in, etc. with minimal loss in resolution for a printed document. I've seen him do similar (but not for a photo) with large, active hornets nests as well (getting a few feet away for no good reason).