So sounds like the little brother regrets so strong that he breaks the laws of time. Okay. Just do it more. Fix more things. Fix it all. Go Re:Zero on us and keep doing it. (I know there's only one more chapter; I'm just making a joke).
Fuck this is confusing. I think Hinata also killed herself that day for some unknown reasons. Maybe she loved the younger brother? But then why did she dated the older brother? Maybe that's why she pretended to not know anything? Maybe she just regretted dating the older brother? Or maybe the older brother isn't as good as we thought he is? Younger brother starting to be a bit likeable now. Shame this is ending in a few nore chapters though