I have posted about this before based on an event that happened to me. At home on the way to the bathroom I got dizzy, lost some motor control and slumped against the wall. I did not fall and was OK in a couple of minutes. A week in the hospital found nothing wrong and it has not happed since. It got me to thinking what would happed if I was single handing.
But then I could have been driving, working on my roof, on a ladder or looking over the edge of a canyon.
My choice based on my risk it to continue to do what I want to do. Having another person on board certainly increases the odds in your favor however and that is the way I usually sail at this time.
If you are going to sail and you want to helm even if you have a seizure it is unlikely that your steering would be worse than mine when I trying to helm, eat and drink and adjust the GPS all at the same time.