This totally a perfect story that showing the high risk of someone who suffered from getting abused during childhood and not getting therapy to heal themselves.
I'm really sad to see how Jaeha died, and how in the end no one is able to heal Yoseob.
Both Yoseob and Jaeha are victims from their past experiences. The saddest part is, no one is totally in fault but at the same time no one is absolutely blameless.
It's understandable how bad Taeoh's feelings towards the whole situations. Like really, you can't say what he did to Jaeha as a mere children's fight, Jaeha had to get traumatic experience twice, leading him to looking for someone who will stand up for him (Yoseob), and making Yoseob's did his first attempt after Taeoh threw water to Jaeha.
Maybe, just maybe, if nothing like that happened, who knows that everything will be so different.
Now that Jaeha is gone and Yoseob is in most likely mental health hospital, he, as the one who remains alive--nothing changed much from his life except losing his friend, will have to take the guilt forever.