2 jars of peanut butter, 4 box of crackers, 8 2L of water, 10 cans of tuna, and some canned fruit she has food and drink for a week when the trucks can't get through and the power is off. If she can't open cans she can use foil and plastic packages.
If she can store extra water like keeping a bucket of water in her bathroom then she can flush her toliet if the water is off.
$15 at Family Dollar for things like a pack of plastic utensils, baby wipes, flashlight with extra batteries, sunscreen, bleach, and hand sanitzer go a long way.
If she takes medicine see how she can get an extra supply 2 weeks would be idea but try for at least 3 days.