I was diagnosed with GCA and PMR about 15 months ago. I am currently taking weekly Actemra injections, but I finished prednisone about 5 weeks ago. I didn't have any problems tapering prednisone down to zero, but starting with the second week I was off prednisone, I started having problems with fatigue, sleep, and mood swings. Doing the same amount of exercise and physical activity that I have been doing all along can wipe me out for a day or even several days. My emotions vary between depression, irritability, anger, and just feeling flat and wiped out. From my research it sounds like I have prednisone withdrawal. Your husband is probably going through the same thing I am. I've read that the symptoms can continue for a long time, like several months to a year, depending on the person's dose of prednisone and how long they took it. I was on a high dose due to GCA.