Originally Posted by VegasGambler

No-showing is fine. If you prefer to cancel, wait until the very last minute.

Either way, keep an eye on that flight. If there is a flight cancellation or even a significant schedule change (I don't remember the minimum amount of time the schedule has to move for it to be significant) you will be due a refund, only if you have not cancelled. It may be worthwhile to check him in (online of course) in case there is a last minute delay. Once boarding starts you can cancel.