I totally understood Sam's lies about his health, because I do that too - as long as I don't acknowledge that something is wrong, it can stilll go away on its own, right? But I'm glad that Dean know about it now.

About the moment between Dean and Castiel, I surprinsingly didn't see the parallel between it and Swan Song, but I found that moment kind of awkward, probably for the reasons you stated - it doesn't feel earned. i think they pushed too hard in this episode.