Homesick question

I've recently read this book, superb it was too but I've been left confused with the twist.

Who was in the kids home? Jesse or Raphael? Uncle Wilbur took Jesse with him for adoption yet it was also Jesse in the home as the kid there was always known as Jesse yet at the end Raphael says it was him in the home and Jesse adopted yet when the kid ran away to swap with his twin he said "Now I'm You, Now I'm Raphael"

So who the fuck was who??