Sometimes there are emergency situations in hospitals that can get extremely complicated. You often see patients without knowing anything about their prior history. A patient comes into the emergency room with cardiac arrest and the pumping machines are going off to give them automatic chest compressions. But at some point you learn about the patient's condition. At this point, the decision may be made to discontinue the life support.
Competency is a very relative term.
There's competency to be able to be President of the United States. There's competency to be able to go to the bathroom and fulfill your basic needs. So there are different levels of competency. For a large segment in the natural course of this illness, these patients are competent, and they should be seen as such. Dementia does not equate with incompetence.