When Alex sees Kurt at the restaurant after 5 years without any contact between them, he jumps up and runs out of the restaurant. The next day, Jake (who was at the restaurant with Alex) sends Alex a note mentioning that the owner of the restaurant (no name mentioned) stopped by after Alex left. Just from this, Alex immediately knows that Jake's talking about Kurt who must, of course, be the owner...I'm really not sure how Alex could have made that connection. Just one glimpse of Kurt in a restaurant he's never been to and knows nothing about is enough for him to realize Kurt's the owner and the man mentioned in Jake's note?