Responses
Don't you love you friends/siblings? You don't have to wanna fuck someone in order to care for them, if you love someone even platonic you protect them and get angry on their behalf. And knowing his relationship with his real family and that she too cared for him, he most likely viewed her as a sister.
It's especially infuriating that the brother proposed to her just out of spite when she genuinely loved him.
Don't tell me he likes that pinkie twink because he looks slightly like his old crush