Thank you for caring enough to get this done - I am puzzled why the vet tested him and didn't suggest it though, and depending on how long it was since he was tested, does depend on if things have changed since then.
CC - I dont get my permanent cats tested - out of all 8, only 2 have been tested, and both on vets 'suggestions' due to health issues, both negative. Ginger could have had anything, he had 3 years on the streets (as a neutered male though, and he was so laid back), lived with a cat with FIP (admittedly they were isolated as soon as I knew, so hopefully that helped with that one). To me, it wont affect what I do for them, and in Gingers case, I couldnt' keep him in, that would have shortened his lifespan more than anything medically.
Forever - no, cats with FIV dont need meds, some studies show Interferon can help, but it is just a compromised immune system, they can live long, happy lives with it.