Yeah, many students gets sent out to study abroad by themselves for highschool (or even as early as grade 8 and 9).
These students are usually sent through agencies that will take the role of their guardians.
It's quite common here, since the parents usually have careers in China that they cannot leave, but wants to send their kids out for a chance at a better future.
Some students actually thrive like this, becoming independent and liking the freedom. While others take freedom a bit too far and just go wild cuz there's nobody to closely restrain them
On the doctor note. I've been using the health services from my university, which lets you book appointments with doctors from the university hospital based on your needs. It works pretty well, the only issue is the long wait times.
Before, most clinics also offer walk-in appointments, that went down since the pandemic though D: