Some have objected to the portrayel of Churchill as altenately vigorous and doddering.
"Some" didn't understand what they were seeing. Churchill went for days with almost no sleep while trying to rally his establishment "allies" in Parliament to fight the Germans. In addition, while trying to force himself to create a speech agreeing to "peace" negotiations with the whole government exerting nearly unbearable pressure on him to do what he knew to be wrong, the internal strife made it almost impossible for him to speak coherently.