This is so sad, unrequited love sure is painful. The brother thing, instead to feel off, I actually felt more wrenched. Like, the tachi sure is eccentric and pushy and kinda sus but he's a good guy, just a sad man. I kind of understood his complexity. I dunno man, I don't think it was unnecessary.
i do not have the problem with the art style though. i think it's cute and matches with the vibe of the manga.