I'm sorry to hear that your cat is ailing. Unfortunately, it's impossible to predict how your cat may respond to treatment or his long term prognosis without knowing what triggered the jaundice. Has your vet done any testing to determine the underlying cause of the jaundice? There are several different types of jaundice with a number of different possible causes. The following link will give you a brief overview.

Here is a link that might be useful: feline jaundice

Jaundice is a symptom, not a disease. Do you know what disease your cat has? Some are easier to cure than others- some are not curable at all. I hope your cat has an easily fixed problem.