So prior to boarding the flight the mother withheld information and used it to get her own way.
Can you be sure of that? Or did she mistakenly believe that a meal was provided or could be purchased on board? She did after all ask if there was a meal she could purchase. Sure, she should have done some better prep work prior to travel, but in past years I've been caught out by what is and isn't available on flights. It varies so much from carrier to carrier. And in the U.S. it's not unusual not to be fed anything for relatively long sectors, something which is not expected from so-called legacy carriers.