Sorry about your friend's misadventure. What did NW say in their defense?

I would always verify my itinerary with NW (via NWA.com) before any flights that I am taking (make that for any airline that I am using). These days flights change rather often. NW usually sends me an email for any changes but not always (I think that I catch the changes before they email me). Always make certain you have a email address with the airlines.

I believe (and I know people will correct me if I am wrong) that airlines expect everyone to check their reservation 24 hours prior to your flights. Did your friend do this?