Headscratchers / Orenchi no Furo Jijou

• Why does Tatsumi live alone in his own apartment when he's only a high-schooler? He's on good terms with his parents, and they apparently live nearby, as his little sister comes over to visit quiet often. So why does he have his own place rather than living with them as part of a traditional family unit?
  • in the manga, it's explained that he is living in his dead grandparents' house because it's closer to his school than his family's house.