I take it back, this actually worked better as a single standalone volume.
The issue, I think, is that Ohana wanted to write it as a one-shot where Mimori was literally a ghost, but changed it to the "was in a coma all along" conclusion because that's what her editor wanted. Which meant that there was no real continuation plotted out for a second volume, after Mimori woke up.
Also the ghosts just don't exist anymore? So Mimori I guess was the only ghost Iku will ever encounter? That was still kind of a weird plot hole in the first book.
Anyway, it takes a while and some pretty confusing pacing and time-jumping to get back to where the first book concluded. With Mimori following Iku home with his dropped book, responding okay to Iku's abrupt confession, then...not bringing it up again until weeks or even months later (? since he'd gone from job-hunting to being employed with work friends). When he does ask Iku what he'd meant about "not forgetting," wanting to know if he'd known Iku before and had just lost some of those memories due to his brain injuries, Iku bursts out with the whole ghost storyline.
And Mimori kind of just rolls with it. Which would've been a good opportunity to dig into that "nice to everyone about everything" issue that got him in trouble with his accident on the bridge to begin with, and which was one of the things he and Iku had bonded over during his ghost life. But all of that kind of gets dropped, too. Mimori's just super focused on trying to live in the present and for the future, to a degree where it almost feels like he's switched into a different personality.
That was another area where it tried to be interesting, with Mimori mostly getting mad that this cute, passionate convenience store clerk keeps looking over his shoulder, waiting for some phantom version of him to come back. And that version never does and I guess never will - even though Mimori has dreams about their coma-time together.
Mimori wants Iku to fall in love with the present day him, just as he is now, which could've been a great storyline if that had been developed. For instance, with those teasers from the end of volume 1 about Mimori inviting Iku over for meals, etc. Which...didn't happen at all in this second volume? Did Ohana and her editor forget those scenes existed?
So while there's some cute enough stuff near the end of this volume, and a happy ending, there's just not a substantial enough explanation for Mimori falling in love with Iku. It still feels bittersweet, but not in a totally satisfying way. A bummer, because there were a lot of amazing threads in this and a ton of potential for a fascinatingly complex story.