Some people can’t vote on election day. For example, my son is an election judge who must be at his assigned polling place at 5:30AM and can’t leave until the polls close. If he couldn’t vote in advance, he wouldn’t get to vote. He voted yesterday at the election headquarters in Louisville just as if it was election day.
I work in a polling place on election day and I can vote there since it is my precinct. Is your son’s precinct different from his polling place?
And why on earth can he not leave during the day? He has to bring his lunch? Or are they that busy.