i think since mc’s brother grew up being controlled, he wants to have something to himself that HE can control and unfortunately, that’s his younger brother. mc said it himself, his older brother raised him. which means their parents didn’t really care about mc (probably bcs he’s not the heir). this gives mc’s brother an opportunity to decide every single thing that mc will be doing.
and the reason why mc can’t have that kind of conversation with his older brother is because he grew up thinking his brother is correct. just like how we are with our parents. whether we like it or not, our parents will always have influence over us. for mc, it is stronger bcs he was secluded from other people. so he didn’t realise how he’s living is abnormal. and since mc & ml’s relationship was only 3 months old, ml didn’t know the extent of mc’s family background as well.
I don't get what his brother want from hangeol . Just have normal conversation where he ask his brother what is his problem and maybe take him to a psychiatrist