I'm surprised the sun isn't on medication. Despite being faithful and staying around, we find out it was the daughter who left that she has always wanted to inherit the inn. If that doesn't drive him into depression...
They didn't invite him to share in family time either.
Why do I get this strange suspicion that he's going to end up an antagonist at some point? :/ Even if it's only short lived and he returns to the fold.
And, yea, I always assume anime children getting drunk on juice is just their way of saying they really drank beer without whatever Japan's version of the moral police is getting their panties in a bunch. Though you'd think with the things children do in anime, drinking beer would be pretty damn minor.