Responses
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Not sure about the ferris wheel part but maybe one of these?
http://www.mangago.zone/read-manga/2345/
http://www.mangago.zone/read-manga/kuro_ouji_no_iinari_ni_naranai/ Ch 5 of this
If not maybe you can try this tag ^ ^
http://www.mangago.zone/tag/ghost/
it was like a ghost bl.. except the ghost wasnt actually a ghost.. but he thought he was a ghost and he didnt have any memory (I THINK>..) and the human that fell in love with him was soo sad when he found out he wouldnt be able to see him again.. i think it was a school life becasue he found the guy ALIVE in a hospital and it seems taht tthe ghost was seperated from his body.. i remmebr this specific scene wehre they were at an amusemnt park infront of a ferris wheel yea/... ITS NOT FOR THE FAINT OF HEART