"Just one person who began to read music again and play the piano,...
Just one out of the hundreds of thousands that have used Donepezil?" ------------------------
Don't shoot the messenger, you asked the question not me.
"She was started on donepezil, 5 mg at night, with no adverse events for the first month of treatment. ... Further, her husband indicated that she was playing the piano again and had an easier ..."
A clear a priori MOA makes experimental findings more believable. I'm sure we'll disagree on the strength of the experimental findings to date but the anecdotes are just not that convincing.
I see F1ash gave you an example of playing piano again. Here's an example of golfing again (among a long list of improvements):