I hope Mike's doing better. Looks like he is. I hope he was up to date on his rabies shot, and they gave him a booster. No need to test saliva, that won't show up there. People or other animals can catch it from being exposed to the saliva though. Unfortunately I have had some extreme education on the rabies virus. When I was little I was bitten by a dog they thought had rabies. The dog had to be isolated 6 months. It was a mean old dog, it did not have the disease and I didn't have to get the shots, but I have garnered a wealth of education about the disease. I won't even go near an animal I don't personally know. Got scared real good as a kid.
My brother died in 2010. I got his cat. Pretty cat, but almost totally feral it reminded me of your story about Mike. The cat was used to being outside and going inside only to eat or when it was cold. I do not allow my animals outside. PERIOD. It's too dangerous anymore. I even had a bear and cougar here in Maryland. Saw them at the house. Makes going outside scary. Anyway, Smokeythecat got out last September. Something whooped his sorry cat butt real good. Bitten really bad. It took 4 weeks to catch him, he outsmarted havaheart traps (they make them for coyotes too), and he went to the vets right away. (I had to use a commercial drop trap and remote TV monitoring to catch him.) He got all cleaned up and a rabies booster, and now he doesn't even think about going outside. He is no longer feral, and let's me pet him and he "boings" around the house he is so happy. I hope Mike will do what Smokey did, and become tame, for both of your sakes. Try some brief head pets to start.