RYOKUNOHARA LABYRINTH: SPARKLING PHANTOM

Hiroki and Kanata have been together since they were children. One day Hiroki is caught up in an accident while trying to save a little girl. The next thing he knows, he is looking down on his own body. Separated from his body, Kanata, and everything else, he tries to figure out just what is going on. Why is he outside his body which is living on as if nothing has changed, how can he convince Kanata that he is there, and who is the strange girl, Fhalei, who keeps appearing for him? — Description from AniList community (anilist.co).