My Asshole!MC cares for her brother, sure, but she has to look out for number one.
By the way, I just have to say that Brasus’ death was masterfully done. At first it seems he just died and there’s nothing you can do about it, then you realize he’s still alive and think you can save him, only to have him die no matter what you do. It’s quite the emotional rollercoaster. I’d usually be upset about him dying no matter what we do but he would have gotten himself killed sooner or later with his attitude.
But hey, at least Asshole!MC is now the only Intelligence specialized team member, thus making herself even more valuable.