I don't know if the author ever lost someone (i think seeing the plot surrounding Mitsuba) BUT DAMN, IT'S HEARTBREAKING SEEING THEM HURT ABOUT HIM ALL THE TIME, like on a personnal level i know how that feels, and it's exactly like that.
I do hope they (and they better) get a happy ending since it's fantasy!
I mean, the whole point of gosht existing and him seeing them should be that you could keep being with them and maybe even end up together and happy since they seem to like eachother a lot!
That'd make me really happy so ya!
Jibaku Shounen Hanako-kun