How does a human body die? When does death occur?
A death of a human is according to the most textbooks defined as a brain death which actually means the termination of brain signals.
That said, for a person which EEG (electroencephalograph) is shown quite as a straight line (similar to the one of an ECG) is said to be dead.
However, although person's EEG might show straight lines (there are a couple of rows each showing a line) when we would say that the person is dead, the person's heart and lungs might still work and there could be almost a normal sinus rhythm of a heart shown on an ECG. This is achieved by intubation. This does not mean that the person is alive but that the lungs and heart are kept in artificial function by the respirator (a machine that inhales and exhales for a patient).
Once the intubation is taken out, due to the deficiency of oxygen other organs will start collapsing which will lead to the multiple organ failure (MOF). This is also part of dying.
Any similar (or the same) case should be discussed with the attending doctor (oridnarius) who will advise patient's family regarding the further steps; its advantages and disadvantages.