How to pay for hospital bills without insurance?

My aunt was admitted to an ER room for 3rd degree burns (scales goes from 1–4). She does not have medical insurance but her husband does (from his employer). They are not citizens of this country and are on a H1 Visa. She suffered the burns after miss handling of a pressure cooker that was boiling beans. What are their financial options? Can you give us any advice ( perhaps from experience of a similar situation)

Thanks for reading.