Welcome @justurtle, Interesting question that I'm sure others may have some thoughts on but then we are patients and not rheumatologists with experience diagnosing PMR and rheumatoid arthritis. Here is some information that may shed some light on your question:

"Can you have polymyalgia rheumatica and rheumatoid arthritis at the same time? It's also unlikely for you to have both PMR and RA at the same time. One condition that does often co-occur with PMR is called giant cell arteritis or temporal arteritis. It is a type of blood vessel inflammation."
--- Polymyalgia Rheumatica vs. Rheumatoid Arthritis: https://www.healthline.com/health/polymyalgia-rheumatica-vs-rheumatoid-arthritis.

"Polymyalgia rheumatica (PMR) is an auto-inflammatory rheumatic disease of people over 50 years, presenting with pain and stiffness in the neck, shoulder and hip girdles1. The term PMR was first used to underline that it seemed substantially milder from rheumatoid arthritis (RA) as no joint damage had been observed2. However, this name may be misleading as PMR is a disease but not a non-specific myalgic or paraneoplastic syndrome."
--- Diagnosis of polymyalgia rheumatica usually means a favourable outcome for your patient: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5644293/

Do you mind sharing a little more about the medication used for your husband's treatment? Has his pain lessened?