I also have major hand issues and wish the connection between the hands and PMR could be better explained. My rheumatologist considers my hand issue as rheumatoid or inflammatory arthritis. He put me on hydroxychloroquine and it has helped, but the hands are still an issue, especially in the mornings. He thinks the hydroxychloroquine will also help with the tapering of prednisone. I just tapered to 6.5 mg of prednisone and am tapering by .5 mg every two weeks. So far that is working well for me.
Best of luck to your husband.