for the pain issues I would ask your vet from metacam as it is easier on the stomach. I would also back away from prednisone as in older dogs it is more agressive on the kidneys. sadly it could be that it is near your dogs time... our old dog we moved from a farm to a city and within three weeks we had to pts her as her eating was next to nothing and she became stiff and lethargic. the vet felt she had cancer and that perhaps the change had been hard for her to cope with. I hope your dog improves.
Meantime I would be going hard at that kennel to have them shut down and lose their license or at least be inspected?
"For every animal that dies in a shelter, there is someone somewhere responsible for its death".