I think a character development that Rei could have made would have been moving on without Sana even if he came back for later parts of the series. I don't know when would be a good timing for it; but, you're right, Rei was struggling with the inability to set his own course because of the car crash, becoming homeless, dropping out of collage, spiraling essentially. And Sana helped him out of the bad situation, but now the next step is to not always rely on her. A hard step, but it very well could be a necessary one. Not just financially, but also because people need to be able to define themself as themself not just in relation to another person.

I wish there was more character development for Rei and his ex-girlfriend, focusing on their reconciliation, visiting his parent's graveyard, and allowing him to go to college. and allowing him to have a have a break from the acting gigs for sana.😢❤

by how old the manga is I think this is the best case scenario for an adult character for these kinds of stories. Even modern manga takes things for the worst if you know where I'm getting at

The story of how Sana saved Rei from homelessness hit me harder than I was prepared for the first time

oh wow.