The ML was diagnosed as a sociopath when he was a kid. Google says that sociopaths or psychopaths can experience a distorted version of love, often motivated by self-interest and manipulation rather than genuine affection. That's the closest ML can love MC.
I understand that... But just remembering what he said when mc was in the operating room should've been a wake up call or something to him.
That's why it took him that long to say he loves him. He won't be able to realize his feelings until that moment where he was agonizing and tormented about what In Seob went through and what will happen to him if he never see In Seob again. It was some sort of turning point to their relationship. After the incident in the novel he was very protective and defensive over In Seob. It doesn't matter if people understand it or not. That has always been his trait.
I don't understand why ML can't tell MC directly he loves him? Why use long-winded words? Is it because what he feels is more toxic love or something?