well technically, the citizens/laity are still supporting that free health care with their labor via taxes and it's typical for more than half of what you earn to be taken by the government for such "free" services. Nothing is ever free in life .
As far as Vinaya, monks at the time of the Buddha had the best health care of the day, so much so that people wanted to become monks just for health care for their ailments, which is why people with so many ailments are banned from being monastics today.
If the laity who run the money side of the monastery want donations to go to an insurance policy for monastic residents, then that happens, its fairly typical for well off places.
otherwise monastics , in America at least, can apply for Medicaid, free limited health care.