Need Help with FIP Protocol

I have a cat that was just diagnosed with FIP (Feline Infectious Peritonitis) The treatment is GS-441524 I think that is Remdesevir. The cost is $13 a day for 84 days. I rescue animals and that cost will be a great hit for me. I have used MMS and CDS in the past. This condition is the Covid thing mutated from what the vet said and I think MMS may help. I have the 2 ingredients on hand to make the MMS. Is anyone familiar with using this treatment and the protocol? I have to start treatment with the GS drug ASAP or my cat will die. He’s already had his lungs drained twice now, so I am running out of time. If I can go this route, it will save me a lot of expense, thank you. 

Sharonanne, see the two animal protocols attached.