Thanks Jana and Warren, for your responses.

The flight was an 11:00 am departure so there was plenty of opportunity to rebook. I'm not sure why a meal voucher was not offered. It could have been through a general PA and he may not have understood it. Nevertheless, my goal was try to find a simple low cost solution to keep him happy with UA and *, for all involved. Unfortuantely, the "systems" in place won't allow it.