In case Rhoda is going to keep him after all, none of us mentioned, an FIV+ cat should be an indoor only cat. Two reasons:
1. Be responsible. If he is out and about, he may end up spreading FIV to others.
2. FIV+ cats have weak immune systems. So even "ordinary" cat ailments can be hard for them to fight off, and can become fatal.

I stopped doing TNRM when I took in Bobby, as I didn't want the ferals coming in with UTIs, and other things.

I remind my vet of Bobby's status each and every time. They tend to get antibiotics earlier, due to the weakened immune system.

Also, for the rabies vaccine:
most cats now get live virus as a part of the shot. An FIV+ cat gets a different shot, with killed virus in it. It is still good for 3 years.

Hope this helps, and Rufus lands with Rhoda or Phesina!