Pardon my scepticism, but I think I'd want to know what his doctors/hospital thought, and whether a death certificate was issued; or at least some other corroboration.
Some people are kept in medically induced comas for quite long periods, to aid their healing; and some might enter a "vegetative state" or "persistent vegetative state," where they're unresponsive to all stimuli. Either coma or PVS patients might be on ventilators or other equipment to maintain their breathing and circulation.