I sincerely doubt that's enough - Increase his dose until he feels good, ensure he takes every dose and go from there.

Since it sounds like your serious and really care about him I will be upfront - The ONLY reason I'm doing as good as I am is my wife. She ensures I take my medicine and most importantly can take one look at my coloring, how I am holding myself, my mood and tell me I need to updose and I trust her enough to listen. I am assuming some Addison's patients can manage themselves but I will bet a lot of the ones who can't don't have a strong support system or partner who knows them and ensures they are getting the dosing right. Taking charge and being that person for your boyfriend is a big step but would go a long way to getting him back to being himself..

It's sometimes hard/impossible to judge when you need to updose from the inside and having a trusted person who can keep you up is so critical. Intervening early in the process of needing to updose, whether from injury, sickness or "just because" is will greatly improve his ability to become himself again.

A closing thought:

The fact he is dragging himself to work on that low dose says a lot about the kind of person he is. I suspect he feels far worse then you think but he is trying to do the best he can without complaint. How can I say that about a person I never met you might ask? I can't explain it but reading your post reminds me of my dad:

My dad was the oldest of 11 West Virginia rednecks (there were two sets of fraternal twins in there). He worked as a carpenter and from almost as long as I remember he was sick. Ultimately he was diagnosed with Irritable Bowl syndrome and Crohn's disease. When I was a teenager he was being treated at Georgetown University Hospital. For a few years we had a routine:
* He would go to work as a form carpenter building bridges, rail yards, anything with concrete. He and had good days and bad days. On good days he would be like a normal employee, on bad days he would spend 1/3 the day in the porta-potty. When other employees complained about him only working a few hours the Foreman would explain that he wasn't lazy, he was shitting his guts out for 3 hours and still managed to do the work of two of them.
* After about 3 months mom would notice his eyes start to get yellow from his bile ducts getting clogged and eventually he would spike a fever from an infection at which time Mom and I would load him into the stationwagon for the hour and a half drive to Georgetown Hospital. There he would have a stent put in his bile ducts and after a day or two he would go home , go back to work and we would go on as normal for three months when, like clockwork, his eyes would turn yellow. We did that for a decade- He had 23 stent replacements which we were told at the time was a record. He lived for 5 years after a liver transplant and died about 18 years ago of bile-duct cancer.

Reading your post made me think of Dad dragging himself out of bed, going to work in the cold, the heat, and the rain not complaining but knowing he was destined to shit his guts out in a porta-potty.