The forgiveness of such a grudge is something I haven't seen in manga, at least the stuff I've read. It's... I don't know if "beautiful" is the word, but it's something. Hopeful, perhaps. That nothing is forever, good or bad. Anyway that's about as happy an ending as it was ever gonna get. Granny returns for the heroic save, Satsuki wakes up, Keita's buccal fat returns, and his brother even gets an appearance to show off his long, lustrous hair, even though he wasn't really relevant for much of the story.
I guess there's another story after this so...
...I'll just be...
....hanging around.
Eh? Ehhhhh?
I have nothing better to do.