So happy to hear your boy is doing better! Another thought; have you tried seeing an integrative vet? There are so many options now that weren't available even 10 years ago. Chiropractic care and acupuncture are some treatments that have really helped dogs with mobility issues. Herbal remedies can also be very helpful when provided by a vet with training in this type of medicine. The nice thing is that these treatments can be used with the conventional meds that are working so well. I hope your boy continues to improve!