It is actually unheard of, I guess. When I was a baby someone killed my family. I ended up in the graveyard and my parents that raised me were ghosts there, that took me in. My other guardian is Silas, but he isn't a ghost.
He can't die.
Or I think he can't die.
Maybe he can die, if someone tries hard enough? Anyway I was raised with ghosts by ghosts. It's just how it is.