4巻の前日譚「みはりと飛び級」の時に劣等感が爆発して言っちゃいけないこと言っちゃった感じで
あの話のお兄ちゃんナチュラルにみはりの事無視してて中々ドロドロしてそうだなって(本編開始時は開き直れたのか楽しくニートやってますけど)

この■■■ちゃんは■歳児並みなんで家ではお兄ちゃんがずっと面倒見てます(昔みたいに
学校ではかえでちゃんが頑張ってるけどそれでも白い目で見られてるし学校から居場所がなくなってきてるし真っ当に学生生活送れてないしで多分遠からず退学に…

At the time of the prequel chapter "Mihari and Skipping Grades" from Volume 4, Mahiro's feeling of inferiority exploded and he said some things that must not be said.
Onii-chan from that chapter just naturally ignored Mihari, but he must've felt pretty messy inside (although by the time of the main story, he seems to have gotten over it and is happily living as a NEET).

This ▉▉▉-chan is like a ▉-year-old child, so Onii-chan is always looking after her at home (like in the old days
Despite Kaede-chan doing her best at school, she is still looked down upon, she's losing her place, she's not leading a proper student life, and she might even drop out soon...