I applaud you for not giving up on Buttercup - I hate to say it but all too often vets tell us to euthanize when it is NOT necessary. Cats with FIV can live long, healthy lives and not necessarily with extra expense. I have friends who have FIV cats (one has 6!) and you couldn't tell at all. So bless you and long live Buttercup. The same goes for diseases like CRF - I think vets underestimate our devotion and love for our furry babies and think we want perfection. This is not so, so please, when faced with a sad diagnosis from your vet do research on online groups formed by cat lovers actually dealing with these issues before taking a step that cannot be reversed.