"Strokes are caused by a lack of blood supply and thus oxygen to the brain."
Minor correction. Strokes are caused by blood clots or blockage in the brain. They can also occur in tandem with heart attacks, or from the collapse of an arterial wall.
Lack of blood and oxygen to the brain result from those events. You're spot on there.
Luckily for him, as a Democrat, he wasn't using his brain anyway.