I don't believe in hitting kids (just not effective) or in violence in general except in special situations, but to me it seemed that in the story, grounding a teen who is physically a man won't do much at that point in his life. For very young kids I can see it having an effect. I actually use them to effect with the kids I teach. Not exactly a scientific approach, but I feel like for a bitter angry teenager like in the story, a more hardass approach like making him take boxing lessons or a military style school or something where he has to toughen up and grow in order to survive would be beneficial. Or just get him to lift weights at least.
I don't know. I think there must be something that is being done wrong. I used to be an extremely angry and destructive young man and I'm sure my parents were completely baffled as they thought they were doing everything right. But if I think back on it now, there were a lot of things my parents could've done differently. A big part of my change was being sent to a boarding school in a different country (because I begged for it) and learning how to fend for myself without my parents holding my hand every step of the way. I hung out with some "bad" gangster wannabes in highschool but that was an improvement from being a potential school shooter. My mom says she tried her best but my dad still thinks he didn't do anything wrong as a father.