There was a moment where the fact that Castiel in this state had no clue who Dean was definitely seemed to bother him, a slight change in his presence which hinted towards hurt. But Dean pushed past that and tried to focus on the fact Cas didn't remember him and not how much that kind of sucked.
"I'm not going anywhere Cas," he assured the Angel. "Look there's something freaky deaky going on here," he started, "whatever's happening Castiel, it's not real, not really."