OK, I'll clarify. Joe Biden's condition of health does not even minimally meet the uninformed layman's label of "brain dead."
"Brain dead" is an unfortunate word/phrase, often used to denigrate someone who is fully alive. It is not an accepted medical diagnosis. Sadly even hospital personnel are heard lapsing into its use in casual conversation.
A person in cognitive decline, such as in dementia, is not "brain dead."
Brain dead correctly defined refers to a long term "wakeful unconsciousness" following severe brain injury from anoxia, now termed PVS, Persistent Vegetative State. Diagnosis and ongoing care have medical, legal, and ethical complexity. Now called iPVS, Irreversible PVS.
In PVS there is minimal to no awareness or purposeful movement. Often breathing continues after being restored, due to the effect of the beating heart.
The case of Terri Schaivo illustrates the complexity of diagnosis, care, legal and ethical decision making in PVS. Terri was in PVS for some 15 years after collapsing at home, age 26, found by her husband and being resuscitated by EMS. Extensive neuro testing and brain imaging confirmed damage from prolonged lack of oxygen. Her husband and her parents battled for years over whether to continue care which included nutrition by feeding tube. The husband as legal NOK maintained Terri would not want to live in this state and would want the feeding tube removed, but there was no living will. Years of legal wranglings over right to life, custody, who could decide, ensued.
In similar cases, loved ones interpret involuntary movements, such as a finger twitch, eye roll, facial grimace as signs of recovery. Criteria for recovery includes 1) consciousness: awarness, consistent voluntary purposeful reactions to visual and auditory stimuli, engagement with others; and 2) function: communication, ability to learn and perform tasks, self-care, etc.
For some, the removal of a feeding tube feels like 'depriving' the patient of food/nutrition.
As usual, ask me the time (is Joe Biden brain dead?) and I'll build you a clock. Hope it informed.
Candy