There are things they don't talk about.
Things like when Dean wakes up screaming from a nightmare, and Sam crawls into bed with him and murmurs hush, Dean. I know. I know. You're safe now.
Things like Sam having a flashback in the middle of a hunt and falling down screaming I can't, Dean, I can't do this any more! and Dean calming him and taking him back to the motel and calling Bobby or Garth or Jo to finish the hunt.
They are scarred, broken things, cracked pottery mended with lacquer and flakes of gold, whole as they are.