I think his requests are reasonable.
A very good advice I got from my occupational physician was to try and be as predictable as possible for my employers and not give them any surprises.

We planned my work schedule in such a way that I will nearly always be capable to handle it and then on better days I could do extras (or not).

Despite my requests I never got approval to work from home (and be paid for it), even though a significant part of my work is from home. ( I can almost always sit on my couch and type on the computer, even if I require respiratory support, but can only come and see patients a relatively small part of the time).

I ended up being formally 85% disability, and practically working half time. Not an ideal solution (to say the least) but it allows me to receive my pension and at the same time keep on working in my profession. It also gives me the flexibility required without jeopardizing my reliability.