****--->Spoilers for 6.20 "The Man Who Would Be King"<---****
In the flashback where Cas visits waiting-room hell, Crowley mentions he has a "certain bald patriarch" he can bring back. I was wondering if this implied that Samuel was in hell, not heaven after all. Either way, the answer to your question does still look to be Crowley.
castiel brought back sam, i'm sure that he believed that sam had his soul too...but for dad, it was crowley who made a deal with him about his daughter...but maybe crowley had the soul of sam and made a deal with Death to bring him back...this wall? really...don't think Death's really clear on it...i think he wants the hell for him and used crowley, dean and castiel...but it's only my opinion..with spn, nothing 's suprised me anymore
