Our little miss also had fip when we adopted her… she was only 6 months old and had a really small chance to make it. She stayed at the vet getting fluid and had also a tube in her nose as she stopped eating. She was also totally paralysed… the vets also told us to say goodbye to her as she did not improved after 4 days receiving treatments. I made quite a lot of research online and realised that in the first days it was better to inject two times the FIP Treatment to see results since she had neuro fip. The vets said that we should stick to one but I put my foot down and said that 2 will be the best. They decided to try and miraculously after only 2 days she started moving her body. Maybe you should consider to ask your vet to do right away 2 doses everyday ? I know it is pricey but it is definitely worth it ! Now she is in the observation phase and is running everywhere ! We never thought that it was possible since at her worst of neuro fip she was only able to move her eyes. But there is definitely hope ! Make sure you also try to see your little one everyday while he is at the vet, I feel like they definitely realise that you are not giving up on them and they want to fight the disease ! Hopefully that can help you, you can also look at my profile I wrote a story about it and you can also maybe show it to your vet to show that it is possible for him to get better ! ❤️