Thanks a lot for this detailed answer with very good points.
When I think about this service, I see it more like a friendly conversation between 2 nostriches, one of which happen to be a doctor and the other sharing his medical condition, looking for advises about it.
This would take place in DM, but if video-chat is added then it would also be possible.
If the “ill” nostrich is happy with the advise he received, he then tip sats to the doctor. No more.
For a more direct and official involvement, Such a prescribing drugs or lab tests, it would require the doc to accept bitcoin as a form of payment in his official practice. In this case, Nostr is more like a way to find like-minded people .