It's still fan theory and no clear answer yet
This? https://www.mangago.me/read-manga/my_ghost_diary
If he is indeed in coma, then it is possible for him to come back to life and properly life with Tsubaki. I dunno if that's the plot here though. They said he 'died'.
I think u were just in very strong denial
Denial is river in Egypt.
From another manwha
For some reason i rmbr the plot being that hes not fully dead but hes in a coma but it could be from another manga