It is so reassuring to know that he is not the only one who does this. I could not mention this behavior to any of my acquaintances without them looking at me as if I were nuts.
This behavior is frightening to watch. However, I will try to get coffee into him after his nap today and see if he will go out for a bit of a walk. Then he can work in the house if he wants. We will see if he is a bit better this evening.
Thanks to both of you.