User blog comment:ImperiexSeed/Supernatural Mysteries/@comment-4343332-20120313223418/@comment-3481504-20120314191501

It's quite obvious, Raphael and Lucifer obliteration of Cas' = death of his vessel, Jimmy, the body he was using.

Actually, more like 1% chance of him surviving that. It'd be like saying Nick survived in "Swan Song" after dispossession.