it might mean its the end of the frendshihp begining of a relationship with each other like saying bye to you friend hello to you lover?
THIS GUY IN YOUR DREAM IS POLITE. YOU MAY WANT TO EXAMINE YOURSELF.
it could be a closure dream. 3 years ago, I had a similar dream about an acquaintance I only knew for a week saying goodbye and how we never took a chance on each other; to me; I think it was a closure dream for me and it's time to move on and stop thinking about could've been. I also dream few weeks later; that he faded away like a ghost, and I was sad.
Sigmund Freud spent years and years trying to nail down dream psychology. And after all of that he concluded that it all boiled down to 7 words: "Sometimes a cigar is just a cigar" True story.