Daikichi’s name means “excellent luck”, but there are some in his life who’d consider him unlucky, suddenly having a six-year old aunt dumped in his lap to take care of. He simply can’t keep working overtime while sending Rin to the temporary nursery school; he’ll eventually burn out. So after consulting with another co-worker who is a parent, he decides to make a professional sacrifice for Rin’s sake.
This certainly means demotion, and the disappointment of his peers, but to my mind, there’s no question whether he made the right choice. By having a set time to go home, he can pick Rin up earlier and spend more time with her. She is a very good little kid, but she is having wetting problems stemming from grief over her father’s death, worry about Daikichi dying, and of course, fearing her own death. This fear trifecta is a lot for an adult, let alone a six-year-old.
I’m also glad Daikichi’s family more or less took the sticks out from up their asses and warmed up to Rin. The way they acted at her father’s funeral was inexcusable (when adults are in a bad mood, the kids feel they’re to blame), and after they spend more time with her they realize she’s not a bad kid after all. Of course, the fact remains, her mom (her father’s maid whom she hates and thus “forgot about”) is out there somewhere. But Daikichi’s actions suggest regardless of whether he finds her, he’s in for the long haul.