I'm so sorry your pet is doing poorly. I'm hesitant to give any specific advice because I'm not a vet, but I think you should mentally prepare yourself for the possibility your vet recommends euthanasia.
Unfortunately, kidneys don't really recover very well after being damaged, and kidney disease is a very common cause of death in cats. If the kidneys are badly damaged, there's just nothing that can be done. According to cat health articles such as this one posted on catdoctor.com, which I quote:
Cats with kidney disease may also develop high blood pressure.
This may cause blindness, behavioural changes or neurological signs.
Your cat's apparent blindness may be a sign that your cat's kidneys are doing poorly. From personal experience, I had a cat with chronic kidney disease that suddenly became unable to walk. It was almost certainly due to the kidney disease catching up with her, and the vet recommended she be euthanized.
However, on a more positive note, it may be the case that your cat's kidneys are still well enough that the disease can be slowed and managed, through diet, or possibly other things your vet recommends. Also from personal experience, my cat, before she had become that poorly, had the disease for many years, which we managed by giving her prescription cat food designed to manage kidney disease.