Hawzah News Agency – In certain cases, some governmental agencies demand that autopsy be performed on the body of the deceased to establish the cause of death. When is it permissible to agree to their demand and when is it not?
Answer: No heir of a deceased Muslim is allowed to give consent for autopsy to be carried out on the body of the deceased for the purpose mentioned above and other similar purposes; and it is necessary for him to prevent the autopsy if possible. Of course, if another important factor at play that of equal or more importance than this basic rule such as securing the life of an innocent individual Muslim, it is permissible.
Source: https://www.sistani.org/