@Ekfreet so what if she kills him that doesn't mean it's over infact that would just put her in danger since he is clearly an influential person. You should think before you put your dumb comment.
So basically they underwent a test where they would have to kill a target or die and I'm guessing there was magic placed to create an illusion where the target looks like someone you love and in order to pass you must kill them but the brother was not able to kill the target hence he died.