Youre so ignorant.
Sangwoo only cares for his own disgustingly psychotic enjoyment and because he has a major Oedipus complex towards him. Bum has extreme stock holm syndrome. If you think that’s caring for each other, you seriously need a mental evaluation, because that is no where near legitimate love and care between two people. It’s manipulation and horrific psychological warfare.
They never said anything about legitimate love or care. Psychopaths are sometimes able to feel some sort of affection or attachment to someone, especially if that person has a resemblance to someone else important to them. Its nowhere near the generic version of love and care, but in terms of a psychopaths range of emotions, I'd say Sangwoo has some form of attachment to Bum, even if it's only for the resemblance to his mother. Its pretty obvious he's not just doing this for fun and while he does seem to enjoy fucking with Bum, it wouldn't be enough to deliberately keep him alive.

For all those people who have been saying he is nice to bum because of the mic.. how about outside? he didn´t have to be nice in the hotel right? i think they do care about each other in teir down psycho way.