rajak01 asked:
What will happen if a person residing in USA without medical insurance met with an accident or other serious illnesses? Will he be treated for free for emergency cases or he will have to go to the prison failing to pay the medical expenses?

You would receive treatment. They can’t refuse to help. If you have no insurance,you can set up a payment plan,or in some cases it can be paid for by grants that they get from donors. Check on this I used it once.