Is it possible for someone who is brain dead to live sixteen hours after life support was unplugged?

It is very unlikely for someone who has been declared brain dead to live for sixteen hours or longer after life support is unplugged. When a person is declared brain dead, it means that all functions of the brain have permanently and irreversibly ceased. This includes the brain stem, which controls the basic life-sustaining functions such as breathing and heartbeat. Without these functions, the person cannot survive without artificial life support.