system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter/Wizarding World] If a muggle born wizard or witch has a close family member (i.e. parent, sibling, etc.) with a medical condition that muggle doctors can't treat, would they be able to seek help from a magic healer like those who work with St. Mungo's or otherwise?

We see numerous times in the WW that physical, non-magic related injuries and sicknesses are of almost no issue for magical medicine, and I would imagine that a magic healer would have the same sense of duty to care for the injured, muggle or not.
gpt
It might not be possible to give certain magical remedies to muggles as they may effect their physiology differently. Not to mention wizards are more resistant to physical injuries so this might also apply to normal illnesses so they might not even have a cure for certain things that wizards are naturally immune to. A muggle would probably need to go to a specialist who would charge more than whatever presumably free healthcare system they have in Wizarding England. Also there are a lot of normal ailments that even magic can't treat. Vision is one of them as evidence by people still needing glasses.