They now have people's names printed to the back of each multiple day ticket, and they will check it. My only experience was being asked my name by the CM at the entrance gate one morning in July when I was using the last day of my 3-day PH (it was essentially "Is your name xx?", to which I responded yes without even thinking or skipping a beat).
I would highly advise against splitting the ticket because the CM may find it odd that your dad is using a ticket with a female's name on the back and would at least want to double-check that it is his name.