I never thought I would see so much copium from one old man. bro really twisted the narrative in his head to somehow make himself believe that the guy constantly getting attacked on the street because of him is somehow “the real bad guy” here. Olympic level mental gymnastics right here.
You should check No Longer Human by Dazai Osamu.
Or if you don't like to read novels, you can at least read Itou Junji's approximate adaptation of the manga.
Oh hey Bungo Stray Dogs reference! I kid of course, but I wouldn't have heard of the author or the book without watching it. From the comments above it seems the book itself is depressing?