I'm so sorry for all your cats health problems, I know how you feel on a much smaller scale. I have a fraction of the cats you have and they have had alot of health issues. I was going to suggest L-lysine but I see someone already did, it's suposed to boost the immune system.

30 cats! wow, how do you have the room for them? seems like you could almost register as a cat rescue, and then I wonder if there are places where you could apply for some financial help? just a thought, I don't know how many cats are considered a rescue.

have you talked to the vets, maybe they can help you with the payments, let you pay the bills off on a monthly basis?