Again, ugh

He's probably in under a lot of stress and pressure since yknow Jeha's getting married, the letter thing and the decision probably caught him off guard. Though he could've handled it better, I understand where he's coming from specially because he literally risked his life so many times for his sister. After a while he will probably support her decision

yeah he just must be so overwhelmed and om edge and just sad....he prolly feels like everyone is leaving him

He's probably feeling like he will be abandoned again. MR has gone through a hell of a lot because of his sister, but honestly she's still only thinking about herself. I mean his sister already abandoned him once to run off with a married man, a married man she KNEW was tied to a mob family. She knew MR would likely be in danger, yet she left anyways. Since then MR has done everything possible to get to her and help her and protect her, and yet now she plans to abandon him again. On top of that, MR is anticipating being abandoned by Jeha as well once he gets married.

ugh ikr imagine your sister leaves for a random person you never knew knowing your life would be in danger then you sell your body so she is safe then she decides to abandon you then the person you express any sort of emotion to ends up having an incoming marriage and nobody tries to reason with you lol

It's because his sister hasn't really been there for him and she keeps getting with bad men and now she's going to become a monk and leave him all on his own

If that makes sense lol