First off, Welcome to GD Hot-Mami, glad to see you found us.

If you haven't already seen some of our articles on detecting if someone's Facebook profile has been deleted or just deactivated, here's a good one to check out for starters: How To Tell If Someones Facebook Profile Is Actually Deleted Or Just Deactivated.

With that said, and not knowing his name, I would take a guess that his name is somewhat common and he also used his (common) name as his "vanity Name/URL" as well? (Vanity name is the one people choose to replace the normal one that just uses their profile ID number). i.e. His name minght be John Smith, a common name, and he used facebook.com/john.smith for his Facebook URL. Although I have never personally confirmed this, I would have to figure that he actually did delete his Facebook account, (rather than just deactivated it), in which case Facebook would have no more need to continue storing his Vanity URL, freeing it up for anyone else to claim.

If (probably more like "when", ) he does sign back up to Facebook he'll end up having to choose another Vanity URL, so you'd have to find him through the other methods of hunting someone down; searching via his name, email(s), last known location, etc.

We also have a thread here dedicated to helping sniff people out : People Search Engines - Finding People