This is an oddly pure approach for a love triangle story about an older brother who loves his younger brother romantically but has to go to a sex friend to cope with his feelings and the sex friend is actually in love with the younger brother who ends up dating the sex friend because he also loves him and then onii-chan is literally lying there bruised, bleeding, and in need of therapy while they talk about how much they love each other...
I'm not usually one to sympathize with the person who has incestuous feelings but that's just cruel to leave him like that. He's clearly being abused and manipulated. I wouldn't be surprised if he was murdered one day honestly.
Maria Boy