FIV is like the cat version of HIV that humans get. Infected cats can live for quite some time if maintained properly. I used to work at a vet and one of our regular clients had a FIV+ cat that came in once or twice a year for bloodwork. This particular cat was being treated with a medicine generally used on humans but I'm not saying they all have to be. I know they had this cat for years and years and he was fat, happy, and healthy.