Okay...
The results are in...
No FIV, no feline leukemia, but he's got worms, ear mites and a uri. He's on amoxicillin for the uri, otomite (or something) for the ear mites, and one pill that I had to force feed to get rid of the worms.
The first time I gave him the liquid amox, he threw it up. I had to force feed him again, and I gave him the amox again and he has yet to throw up.
Pooped in his blanket on the way home from the vet, peed on a throw pillow once we got home.
*sigh* Pray it gets better from here?