About a guy who is a pushover older brother who takes care of his little brother. He makes him a bento, drives him to school and takes him home like a literal butler...
He eventually gets tired of this and decides to move out and live in an appartment with a friend of his but ends up moving ut and living together with his little brother. His little brother isn't his actual little brother.
The little brother eventually confesses... or well kisses his older brother. But the younger brother loves his older brother, since the first time he saw him.
This Is Taking Brotherly Love Way Too Far