I was in the same dilemma.

I found that the insurance (I think they call it travel or short term insurance) covers only accidents and emergencies.  Even then, they usually ask that they be sent to home and will pay for air tickets.   Not  really helpful.

Instead, I have opted for inexpensive neighborhood clinics.  Yes you do pay, but not as much as what the market cost would be.  And in case of emergency, you have to take your parents to the ER where they will be treated and you can always negotiate the deferred payment options.  Your vehicle and home insurance will cover them as well if they are traveling with you should - God forbid - accident happen.

I know, not much of help from my posting, but thought I'd share my views.