I don’t think pragmatist is the word I’d use for him. I can empathize with the annoyance of things changing, but a pragmatist wouldn’t be this inflexible.

Given his other writings and the fact he hits things when they anger him, I’d go with curmudgeon. A word harsher than I’d like, but it captures the essence. He seems angry at the world around him and does not like adapting to it.

This is pretty common but most people don’t take it this far. :)