So the friend is Homer!!!!!
I don’t think the friend is Homer, I think he’s a reader of the stories within the story. You can see the name of the authors on the books in the last part, a modified Homer for the Iliad and the Odyssey then a snippet of Choi Hyun-Min for My Calypso. The friend seems to express surprise at the twist of Calypso falling in love with another human in My Calypso following the Odyssey. Then like the comments before breaks the 4th wall by addressing us the readers of this story.
Sorry for the long post, that’s my take on the ending. (≧∀≦)
I'm losing braincells trying to figure out what's going on. At this point I don't even know who's who. Somebody rescue me from this suffering