It's not necessarily in an incest-way (romantic/sexual). I believe it's more likely just about control, treating her like an object that belongs to him.
I don't think so. I'm assuming he doesn't like Ariel and the younger bro he killed cuz their from like a different woman. But considering the time frame this is portrayed in, I'm assuming it's about the whole "male domination" shit so to assert some control over her as the person prior to me said
Does the brother like her in an incest way or something? He’s so touchy with her and she looked so uncomfortable being around him.