Wife and I are both on flight. We both have companion pass. I need to get one other person (my companion father in law) on the flight. This was my fault for not issuing the companion passes earlier but oh well live and learn.

Flight is sold out - was told by Southwest to keep checking it online but it's 2 days before departure (due to leave July 1) so not holding my breath for cancellations. Is there some better way to get this done to get him on the flight? Has anyone shown up at the airport on a sold out flight and get issued a companion pass standby ticket?

Alternatively I could book him on a flight later in the day on points and we all go to the gate counter and see if they will issue him a standby companion ticket?

Due to the way southwest works last minute flights are not efficient use of dollars/points and we don't want to go without the father in law...