That isn't a totally unlikely possibility, as evidenced by a few of the vids. that surfaced lately.
On the other hand:
even though I agree that it's not ok for a politician to hide such things and to continue in the race if (s)he has such a severe potentially impairing illness, and even if her illness woulnd't in any way soften my view of her (a corrupt dubious politician),
Illness is nothing to joke about, no matter who has it.
Whether Hitler had Parkinson's is certainly not certain.
Discredited second-hand accounts do not make a diagnosis but they do make a poor link to Clinton, no matter what her qualities as a candidate (and personal health).