So Kyle was slowly dying, had no power and quite simply couldn’t physically do what his family could so his “father” thought the best way to deal with him was to torture him with exercise he couldn’t do then call him useless and say he doesn’t want a son like him?
But somehow it’s the literal child’s fault he has mental health issues? Maybe next time treat him with love and kindness.
And of course the MC, who never liked Kyle and blamed him for everything from the get go, gets all the benefit of Kyle‘s suffering without ever acknowledging it was the family who screwed Kyle up in the first place.