68? That's really inconsequential and not all that unsurprising. And not likely any kind of plot by anyone involved in elections either. More like individual family members who receive grandpa's ballot in the mail and decide to send it in (for grandpa, you know)
I could buy your argument if people turned in an absentee ballot requested by grandpa, who then died before he could mail it. But 8-10 years after gramps dies?
In Florida, you have to request an absentee ballot and give all sorts of information. They don't just send you one year after year.
My family comes from Jackson, Tennessee, and they make them strong and opinionated there. If anyone could vote after death....