Spare tire in a can
Buy her a couple of cans of “Fix-a-flat” or one of the other canned tire fixes, show her how to use them, and where they are in the trunk/boot. These products won’t fix all flats, but in many situations they will get her home.
Hint: The cans with a plastic tube attached take less strength, but can a LOT messier than the cans with the top that goes directly on the valve stem. If you get the hose kind, toss in a pair of latex gloves for her.