The animal control folks should count themselves lucky it wasn't a skunk with armament intact. People have certainly kept them as pets; I think I've heard the term "woods kitties" used to refer to them.
... On the one hand, there are rules against domesticating wildlife, and good reasons for them. On the other hand, once domesticated, returning her to the wild really isn't a Good Idea.
So he's likely to be fined, but I'd flip a coin on whether she'll be zoo'ed or returned to him on condition that she be neutered and otherwise appropriately vetted (in particularly, she Really Should be getting rabies vaccine),
A lot will depend on how he acquired her. If it was a matter of rescuing a kit after her mother was killed, the authorities are more willing to look the other way. I have a friend who reports having had a pet bobcat -- but they went to the authorities first to get permission, and since he was a male of a more threatened species it was easier to argue that having him remain in the area and unfixed might help maintain that population.
[As a kid, I went to an Audibon Society camp. One year they had a trio of raccoon kits that had been rescued and whom they were trying very hard NOT to acclimate to humans. Us kids were told to keep some distance between us and the cage, and only one staff member -- who knew exactly what he was doing -- was allowed to interact with them. He worked hard to remain threatening, and in particular to make sure they didn't associate him with food. Both difficult; they're bright, and they are unbearably cute.]