Still why brother hates Yoon so much? Why mother hates him too?

I also want to know

I’m sure that he is in love with him or something like that because he didn't show up and eat until Yoon came back at his mom’s house

WAIT WHAT

Well I don’t remember the chapter but the main character left his house for three days and the brother didn't leave his room at that time. Until the main character came back he left his bedroom to talk to him and said if I remember well that he was waiting for him or something like that

Damn bruh, the brothers confusing as hell