If Sam had told Dean about his dreams...

[Bela Talbot]

In Bloody Mary, it's revealed that Sam had prophetic dreams of Jess' death, but he doesn't tell Dean. Would it have made any difference if Sam had told Dean about that then?

 

[Gabriel]

I don't think so. I don't think Dean would have believed him to be honest. They would have found a way to discount it. Especially at that time.

 

[Death]

I don't think they were that close, that Dean wouldn't have freaked out, I can't see how telling Dean would have helped.