It's both a good thing that Frank smiles at him, and a bad thing. It's good that somehow, in his oddly reduced state, he recognizes Dean enough to find comfort in him, but at the same time... he wants his definitely-NOT-boyfriend back to his normal, asshole self.

And just like that his wish is granted and FDR walks in through the door, and Dean has that moment where he turns to stare at him.

That guy's wearing the right clothes and he's got that shopping bag that was expected- and his reaction sounds right, but then...

"SHIT-" Dean flies back from the guy on the bed and looks back and forth between the both of them. "WHo are you?!" He finally asks the one decked out in shiny black leather.