I took methotrexate for 5 months or so for PMR. Nausea was bad the first week or two but I persisted because I hadn't been able to drop prednisone below 7 mg. The drug allowed me to drop to 5 mg but then it seemed to stop working and my liver enzymes went high so I got off it. If I were in your husband's situation I would try it. It's important to keep inflammation under control but I'm not sure methotrexate could prevent GCA. That's a good question for his doctor.