(Not marking it as spoiler because I don't think it is) I really like it when any kind of story drives something important home without spelling it out, especially in a 1st person narrative like here, I think it's a sign of quality, and in this case it's the relationship between Heejae and his adoptive dad. Like even though Heejae is often dismissive of Mr Hong it's clear he actually respects him a lot and he's possibly the most important person in his life who made him the way he is. He seemed to be a very troubled kid and the fact that he has a conscience and a sense of ethics and responsibility seems to be all Mr Hong's doing.
(Not marking it as spoiler because I don't think it is)
I really like it when any kind of story drives something important home without spelling it out, especially in a 1st person narrative like here, I think it's a sign of quality, and in this case it's the relationship between Heejae and his adoptive dad. Like even though Heejae is often dismissive of Mr Hong it's clear he actually respects him a lot and he's possibly the most important person in his life who made him the way he is. He seemed to be a very troubled kid and the fact that he has a conscience and a sense of ethics and responsibility seems to be all Mr Hong's doing.