Present Day
Dean was gone before Sam had even finished the first line of the exorcism. He just rippled and disappeared and that was that. No more ghostie.
Sammy had a feeling that his brother wasn't really gone, that he was staying just out of sight, somehow, trying to hang on to what he had left.
He closed the journal, deciding that it was probably easier to let Dean figure things out on his own than to force him into some other dimension.
He was gone. Really, truly gone. No body to bury, no bones to salt, not even a ghost to deal with. Just… gone.