Stoney Service Dog Knee Surgery

My name is Mark, I have a tramautic brain injury. I have a Service dog named Stoney who helps me with anxiety and seizures. He likes to sleep next to me on the bed, but recently he has been diagnosed with an ACL tear in his left knee. He hurts every day and this just kills me to watch this. I would rather trade places with him.
I am on a fixed income and unable to afford Surgery for him in Twin Falls. Can any one help? As soon as I can get some funds I can schedule the surgery. Thank You. Took him to the Vet again today his knee is worse, and now his right knee is bad too. What am I to do?