Parents want to return to China when they get a green card in the United States. Can they still enjoy free medical care in America?

If you don't live in America for a long time, your green card will be confiscated. Free medical care refers to local medical care in the United States. If your parents bought better medical insurance in the United States, some foreign-related hospitals in China can use it, but it is not clear whether it is completely at their own expense. It depends on the insurance your parents buy.

In addition, as far as I know, free medical care in the United States is a welfare for low-income people, which is different from that in Canada and Australia. If your parents immigrated from relatives, they can't enjoy low-income benefits, and their sponsors have to pay the bill. Unless your parents become citizens themselves, their protection will be cancelled.