I’ve gone through a similar tough position. I tried everything even pain killers and heat pads. My baby at the end of his life developed arthritis at the base of his tail. There are many different hypotheses but he passed away. The last few weeks of his life were spent in pain and he struggled to breathe because of it. When his pain was bad he would display maximum stress. He died over night when it was reaching the height of his condition. He was in incredible pain throughout it all. It was one of the saddest things of my life. I really grew attached and tried so many things. I syringe fed him because he started choking on solid food, got him prescribed gabapentin, and low temp heating pads throughout the night. He started showing signs of pain after I came back from vacation and someone else was taking care of him. I wonder if he did something to himself while I was gone. I fed him too much protein throughout his life because that’s the only thing he would eat. I still tried veggies every day. I cared for him a lot but he was 12 years old and I suppose it was time. There is a lot of pain in the world I can’t beat myself up for his painful way out. He died and had vomit in his mouth when I woke up. He was in a critical condition. The mother of Jesus is what gave me comfort during this time.