They should have bought extra water and food back in early June at the latest. You can always used it up after Thanksgiving.
Better yet, donate it to your local food bank after the season. I remember after Hurricane Andrew, the area we were in was not directly hit so we sent the extra supplies we had bought for hurricane season (including baby diapers because my son was not quite 2 yet) along with relief items that were being collected at the hospital. To those who say they are on a fixed or limited income, it doesn't take a lot to stock up a little at a time during your regular grocery trips (pick up one extra can of something throughout the year) versus having to run out at the last minute and try to gather stuff because you weren't ready.
At the beginning of hurricane season every year the National Hurricane Center advises people to prepare THEN for hurricane season. Just like people up north prepare for blizzards. Common sense would go a long way but seems to be in short supply in this country these days.