Responses

That is the point, he is not very "sane" to being with. His father use to beat him up and his "friend" helped him during that time, so he is clinging to his friend because that's the only kindness he knows off. That's why toxic relationship are so hard to get out off, you keep hoping for the things to go back to the way they use to be / get better but they never does.
It's really Haewons fault
Letting them ruin him over and over so frustrating
Killing himself would be more dignified