"I don't know what you've been smoking, man, but you should get a new dealer."

But even if this guy's on something, that doesn't account for him knowing Sam. Maybe from Dean's memories?

Dean is beginning to feel less and less comfortable riding this horse next to this guy, but he isn't willing to leave the injured girl. He's just gonna have to stick it out.

He readjusts the woman's head and makes sure to keep Dan within his range of vision. If this guy's unstable, who knows what he's capable of.