How much is that irrational fear worth to you? In the end that's the question that needs answering. Very soon, you'll be paying extra to buy a petrol vehicle. And that's before you drive it anywhere and get to deal with taxes, fuel cost, and maintenance cost as well.

In any case, a typical EV would have about 50KWH of battery; more than enough to power a house for a while. The more EVs there are, the more stored KWH of energy will be around in any area if a blackout happens. Much more useful than oversized SUVs burning up all the remaining fuel in your area while fuel logistics are being disrupted.

For your parents, an EV and vehicle to grid technology could have seen them through those 3 days. More, if you drive it to some fast charging access point in between to top it up for 10$. It's perfect especially for remote setups. Add some solar panels to the mix and you are basically not dependent on the grid.