Looking for some positivity

2 weeks ago our tuxedo had an accident jumping out the bathroom window when he spotted another cat in the garden and developed a limp so we took him to the vets, he seemed to deteriorate over the next week so brought him back for more tests and it was discovered he had FIV, possibly since birth but hard to tell as we got him as a rescue 6 years ago, never showed any signs until he stopped eating this week, he also shown as being anemic and we have a referral to a specialist college veterinarian service tomorrow, all I can think about is the worst possible outcome and would love to hear of recovery stories to give me some hope.