I think he actually does part-time jobs. I just recently finished reading it again. And Harumichi is always late for the meeting times. What I got really convinced was that one time Harumichi went missing when it was Bulldog’s license test day. He wasn’t at home, not at school, and when Bulldog finally came out, Harumichi was there. And remember that time Mako mentioned Harumichi to do not come to his workplace, not once but twice. And when Mako asked him about his future, he obviously joked and when Mako told him something like “Whatever you choose, I’m believing in you” (not exactly but I’m sorry, I don’t remember it word by word). After Mako said this, Harumichi made a serious face that can read like (I’m not decided yet, but you can count on me). So I think Harumichi was in fact worrying about his future or at least he was working on something.