Adrenal Insufficiency and Tapering Prednisone

Hi friends- Does anyone recovering from PMR have experience getting diagnosed with and treating adrenal insufficiency?

I'm curious about how you and/or your doctor realized you should be evaluated for adrenal insufficiency, what symptoms did you have, and how did you confirm it?

My dad was diagnosed with PMR in May 2022 and has tapered down to 5.5 mg. Since January, he's been having trouble getting below 6 mg. We've had about 2 instances of low-grade fever and intermittent extreme fatigue, but he also has co-occurring conditions that could cause fatigue, and he's unable to communicate well, which makes it hard for my family to determine what's going on.

After the most recent episode with low-grade (99 degrees) fever that lasted two days, his rheumatologist sent us a message advising to get his labs done this week (ESR and CRP), and "I'll also add cortisol in case he has adrenal fatigue from being on prednisone for so long."

I'm going to reply to her message to ask if there's a certain time of day the blood should be drawn and if it's before or after the prednisone. All of this has been very hard on my family. My dad had a severe stroke 2 weeks after being diagnosed with PMR, he has physical as well as cognitive disabilities, and managing everything with PMR and a prednisone taper is just...sometimes it feels impossible. It's also no picnic to get him to doctor's appointments and blood tests. It's so frustrating to feel like it's one problem after another, and unfortunately we haven't always been able to trust his care team to be considerate of the whole picture. His rheumatologist is good, but I also want to make sure we're not missing anything.

I wondered if any of you have had experience with this?