Yay! And yeah, he sighs and complains and then does whatever people need him to do anyway because he's just a good kid that way but that also feels like a little brother kind of thing, especially if the older brother is a punk. He'd have relied on him a lot after their father died for sure while also trying to look after Misaki if he needed it (and of course after their mom). He'd cover for him, too, depending on how much of the punk side Mao got to see before Misaki moved out. If he was sneaking in at night, Mao was definitely there to open a window for him and tell him he was never doing it again until the next time.

He'd call him Misaki if that's what Misaki wanted, or we can come up with a nickname since it seems like Misaki doesn't like his name? Either way, though, yay brothers! And he definitely grew the last bit since Misaki moved out so every time they see each other now Misaki gets reminded that he's the little one, so there.