User blog:Cuvince/The Return of Bobby?

Where do ghosts go when they die? I know early in the show they said they just cease to exist, but that was long before Purgatory was introduced. If I'm not mistaken, no one on the show has ever said dead ghosts don't go to Purgatory. If they do, does that mean Bobby could be in Purgatory and might be able to help Dean out?