I had a rescue kitten with Coccidia. He cried in pain when pooping. It took 3 rounds of Albon, but that finally cured it. My vets said there were some other drugs that could be used if that didn't work. I think one was panacure. If I were you, I would get a second opinion from another vet...
Suppose you don't care a thing about ever breeding OR showing, or even "papers" for that matter, Could you find a "doll-faced" persian or even a look-alike? All that would matter would be a healthy kitten...