I'm assuming one of the brothers died, who's the mc tho older or younger brother I wonder

Like I think younger but towards the end of the prolog i get a bit confused well it's only a prolog

The most plausible scenario is that the older brother died imo

I think ml is the brown hair guy. From the look of it, it seem like ml accident or probably left both the brother or sth happened, idk, and then later sth happen to the brother which whoever that guy was kill one of them and smack their nose bc it look like that. Ml probably is the one looking clue as to who kill the brother. And he did said it was a hater and love relationship, so I think it is relate about when he left them. Just a guess from the pic.