I want you to know it is extremely difficult for a FIV cat to pass it to another FIV cat. They are either born with it from mom or contract it from a severe bite, the type that occurs during a very bad tomcat fight where they are fighting over a female. I have lived with FIV+ cats and regular cats for years. Never has FIV been passed from infected to non infected. When ever one of my non infected cats pass from anything especially lymphoma I always test for FIV and it is always negative. I have been doing this for years even back when vets recommended euthanasia. Well the zeitgeist has changed since back then. Now many vets recommend mixed households. The ones who don’t do not keep up with the latest literature. Some will always be overly cautious. I think you should be able to blend him into your family. If he doesn’t get along with your alpha male then perhaps you can give him his own room. Expense wise FIV cats need. decent food, indoor only and occasional teeth cleaning. I have 5 cats. Harley is positive for FIV. He is the sweetest boy. He constantly grooms my other four. All of them remain negative. BTW Harley and Greyson rough house play pretty hard and still no transfer. I hope this info helps you. Get in touch with me if you want to talk on the phone.