I'm guessing that Mr Money would either rebook the ticket to fly back later or would buy a new ticket (from WN, we hope) to fly home later. Both tickets (paid and companion) would have been rebooked, but companion can't spend another fourteen days at the destination. In the extreme, Mr Money receives the bad news at the airport if the airport has a testing facility, so clearly this was unanticipated and documented.

The comparison is the money that WN could have made if the paid and companion tickets, for both Mr Money and Mr Freebie, were rebooked to travel about fourteen days later.

I can see an argument for an above and beyond compassionate exception.