@Bad5Company
What an ignorant thing to say.
Friendly reminder to everyone - if you suffer from psychological problems in Japan, you're in deep shit. Psychology and psychiatry are not well accepted and in fact there is heavy stigma against people with mental disorders (it says something that, in Japanese parlance, such disorders are often summed up with the term "speech impediment", because heaven forbid you admit you have such people in your family, that's an assured way to shame everyone involved).
Nazuna's brother is a pretty obvious example of someone who's been broken badly (thank the pedo stepfather for that). Now I don't know if the manga exaggerates, or if he really was that messed up, but where he needed help (and that means professional counseling and prescriptions, not "a punch in the face") he was left to his own devices because, again, people like him bring shame and unwanted attention to the family as a whole.