No, not really. Losing your place in a speech is something any one of us who are over 50 are prone to do. You can even do that as a youngster with a completely healthy brain.
The last thing that I would ever do is defend Hillary on anything. I can't stand her, but she does an OK job of giving her filthy rotten speeches for someone her age, IMO.
We should go after her on the issues and not get mired on something we can't prove. If she does have brain issues it will soon be impossible to hide.