
I'm one of the previous translator (Chas). You can read the other chapters on wecomics so that you can support the author there. Ch 1-20 is free. You need to collect shells daily to read the following chapters. Maybe the current translator stopped updating it because it's now available in wecomics. Correct me if I'm wrong.

I didn't get the last extra chapter. So uhm he's not dead? Or it's just a sequel showing what'll happen if he's still alive?

I think the same as you, maybe the author (to make it not so painful) made an extra chapter were they showed both male leads happy and alive. That is what I got from it, they are in the present and the ghost boy (idk his name) is still with his illness but now he as reunited again with the love of his life.
Still, I am not sure about the meaning of the last 2 panels, but my guess is that he woke up after "going to the after life". I am mainly basing this theory/idea because Choi Hahyun has the same outfit and is in the same position as the last panel before going to the memories of both. But maybe I am wrong and in reality the soul went to the afterlife and the rest was made for the readers to be at ease.

Basically if you read through the whole chapter note ( idk if you did ) it states that Habin ( the ghost ) is still alive. the soul that was following hahyun is indeed habin but the soul was only detached from his body because habin was in a coma, and another clue that habin was still alive is the green plant in the patients room, it suggests that habin is still alive due to the fact it’s his plant and it’s still there and growing. in the end habin never really died and it wasn’t just another story for a happy ending instead of a sad one it was indeed the actual true ending. Also to answer your last question the last panels in the last chapter is showing when habin got back to his original body and woke up from his coma :) i hope this helped you understand

I just read the author's note and it was uploaded the day after I comment this lol so my theory that habin is in a coma is really what happened lol I also noticed the plant so I had the idea that maybe habin was connected to the plant and maybe he was alive and he was just in a coma. Now I can RIP my mind knowing it was a happy ending
It's good that Jihwa knows where his place is. I know he's not that stupid to do such things just because he got rejected.