GlisteningRain's manga / #Sequel(6)

I don’t think that Mimori recovered his memories at the end. In my opinion, the ghost version of him disappearing symbolizes how he was able to rediscover his feelings for Iku and not necessarily his memories. Mimori’s hazy memories of Iku was probably due to his ghost version urging them together, and once that was accomplished, he disappeared. TL;DR - Mimori emotionally reconnected with Iku even if his memories didn’t return.

Chapter 7