Do not pay his medical expenses and let him sue. According to The General Principles of the Civil Law of the People's Republic of China Article 106, Paragraph 2, it is stipulated that "Citizens and legal persons who, due to fault, infringe upon the property of the state or collective, or infringe upon the property or person of others, shall bear civil liability." However, the compensation responsibility that the perpetrator, including the patient, shall bear, can only be reasonable losses corresponding to their fault or negligence in the traffic accident. Medical expenses, hospitalization fees, lost wages, meal subsidies during hospitalization, and other losses that are unreasonable—such as those arising from a patient refusing to be discharged when eligible—do not have to be borne by the patient.