That friend knows he doesn't like him and that he is confused and still takes advantage of that to make a move, people like that dont give a f*ck about your feelings, they only care about themselves
Yes but Junyoung is using him too. Junyoung isn't a people pleaser type so wouldn't just go along with someone if he didn't have to. He's testing his feelings, and obviously still has an emotional tie to SD, so couldn't go through with it. The friend does care and wouldn't be the first person in history to try any advantage for the person they harbour emotions for.
I feel a bit sorry for the yellowed haired friend, but mostly for SD, as he has no idea why it's ended. Well he'll find out soon enough.