The kitty is beautiful. I am so glad you are adopting him/her!
Of course your vet is going to be the person you need to talk to the most, but for now I can tell you that getting kitty inside and away from a stressful environment of any sort of shelter will help to improve everything! I wish your vet had been a little clearer with you. I can’t totally tell you the details but I can tell you that FIV cats can continue normal lives. It’s a virus. You don’t say how old kitty is. Younger kitties can get test results on this that can change. The URI can be treated. The anemia can be treated as well. You also don’t indicate the name of the blood parasite but that is also treatable. Kitty needs a good diet, a loving environment, some medicine, to be kept indoors, spayed/neutered according to when your vet says they are up to that and regular vet checks. I am guessing the vet will administer antibiotics. I have had two kitties with blood parasite and that is what my vet did. I have also had cats with FIV and they had normal life spans and good lives. They got antibiotics as well if they got sick. I made sure to boost their immune systems with very good diets. But, I do all the above mentioned things for all my cats. You can do more specific searches here on this website but I think the best thing is to find a time when your vet can explain it all in detail to you. I know it’s worrisome if you don’t get specifics. 
My best suggestion is that you pin the vet down for more information on this particular kitty. The kitty has gorgeous eyes! Love, love this kitty. I expect others will be responding to your post. Please keep checking in and update us with what the vet says. My kitty, Whistle, sends greetings. He recovered nicely from anemia ( caused by parasites) when he was younger.
He is a happy and healthy cat now.
