If you only did the 12 test, it is not uncommon to have lots of matches. You need to refine by doing the 37 or 67 test. Why are there no surnames like your son's? Because no related man that has that surname has tested. Or perhaps the surname was changed at some point. Or perhaps when surnames started, different families took the same surname but were not related genetically. Or perhaps there was a disruption in the male line, due to undocumented adoption, or different paternity.
If your son is one of the varieties of R1b, it is not unusual to have no matches, at 25, 37, or 67, but have lots of matches at 12. The closest match any of the three men in my family, brother, cousin, and in-law have, is the cousin who has a 60/67 match. And not with a family surname. This common ancestor would probably been before the 1600s. and neither has a genealogy back that far.
You need to test paternal uncles, cousins to find close matches.