Responses
Just assumptions, he knew that his brother liked him in a sexual way. Thats why he monopolized his brother's feeling by dating others. So that he gets agitated to take a step further. I think he liked his brother too as when towards the end when he finally called his name he was pleased with it. And when he says he is the only one for him, i personally think its vice versa feeling for them.
Maybe bcz he knew that his brother like him...so he wanted to see his brother in pain
and jealous bcz of him by dating other girl
Don't get me wrong, i enjoyed it, I'm just so fucking confused lmao so like did the other brother also like him??? Cuz if so why does he have a gf and stuff?? Like huuhhhh?