Just tell him you're embarrassed about it. That's what I do and I think it helps people know how I feel.

And let him know that catching up before an appointment isn't always the best, but you might be able to after the appointment, depending on how you feel.

Tell him that recovering from a brain injury takes a lot of energy, so people in recovery are a lot more tired than usual and unable to do as much as they could before the injury.

And then tell him that because you're energy is so limited, that doing things that aren't pertinent might not be good for you recovery, that on some days, catching up might take energy away from having the energy to eat or shower and that when you then do those things, it takes energy away from the brain healing itself which prolongs the process.

Hopefully then he'll understand.

Some of my friends don't really understand either, but they at least accept what I tell them and try to understand it.

I think him arriving 30 minutes early is ok, because it allows time to get ready to go. But I'm slow and I live in LA, so I need buffer times like that...