hi book, i am sorry for your dear cat.. i hope he gets better soon.
also i have heard of alternative therapies for pets too.. sounds strange but i saw my best friend's dog dying of cancer and homeopathy saved her... she is 18 years old.. and playful and running around as if she was the youngest dog ever... so perhaps there are similar options.
if it turns out he needs treatment and someone to commit perhaps you could hire someone from a vet hospital to go check on the pet... or ask a friend, family or neighbor to do it for you.. also, when my cat Dolce was also suspected to have a bad disease the vet told me sometimes treatments are painful and people prefer to put the pets to sleep. it sounds harsh but if I knew my cat was suffering a lot that would be the most compassionate thing to do.
Hugs and I hope you two feel better soon! put it in God's hands.