The difficulty with "functional fluency" is that medical terms are extremely specific. On top of that you have to deal with "doctors in X recognize this illness

The difficulty with "functional fluency" is that medical terms are extremely specific. On top of that you have to deal with "doctors in X recognize this illness, but doctors in Y recognize it as something entirely different"-style stuff. Alergies can be a scary one to get wrong, too! Of course nobody owes anybody anything. I do think that in countries with nationalized health care, at the very least having a call center to help out with language difficulties around this feels like almost a no brainer though. There are doctors with specialized dictionaries and the like as well, of course. And... yeah honestly, Google Translate (or my favorite solution of "go to wikipedia page and find the linked article in local language") can help a lot.