I dont know about you but Hillary Clinton sure didnt look like this sick dying woman that collapsed on 9/11..maybe it was all an act and there is nothing wrong with her, or they have her drugged up who knows
I think whatever is wrong with her is something that is intermittent - not constant. It could likely be mitigated somewhat by medicine and she has, at times, appeared oddly hyper on the campaign trail (the Chai tea head bobbing behavior was downright weird even before she lost control of her head).
She is clearly running a limited campaign in terms of personal appearances and/or taking questions. That, by itself, will not set well with most voters who want to see and hear the candidate - not surrogates or ads.