Severe joint pain , back pain , prednisone

My husband is 30 years old and is having severe joint pain and back pain. Fatigue, depression, not sleeping because of the pain, hand swelling, and the bottoms of his feet will hurt sometimes too?? The doctor has him on prednisone right now and he seems to be doing better for now but, I know that he can't stay on this medecine. His doctor won't listen too us and just keeps prescribing more drugs instead of running test. Right now he is on Cymbalta, Lyrica, and Mobic and prednisone. What do you think is wrong with him? The medications he has been taking hasn't helped. The only thing that has helped is the prednisone.