I've been playing around with battery-based "portable power station" devices and charging them with solar panels. The solar charging is optional, they can be charged from AC power or car "cigar lighter" ports as well.
Here is a smaller and cheaper model of a high-quality unit that I got for half off a while back:
BLUETTI AC50B Review (My thoughts)
That one runs about $270 to $300 on sale, though there are cheaper brands. Just look for the features needed.
While these have several obvious uses, they can also serve as an Uninterruptable Power Supply (UPS) for things like computers... or even medical equipment (oxygen concentrators, CPAP machines, etc.) that older folks may be dependent upon. They can be plugged in, charging until full, while at the same time passing AC line power through to the attached equipment. If the power fails, the battery and inverter take over.
You'll probably want one scaled to power critical devices through the night 10 hours to even 24 hours. Anything larger is going to be very heavy and much more pricey.
One of these could even be used in the car for a long trip. Many oxygen concentrators are designed for portability, but they need power. Instead of lugging an oxygen tank instead and worrying that it may run out, you could power the concentrator in the car from one of these power stations. They can even be recharged from the car "lighter" port at the same time.
At your destination, drag Granny inside with her concentrator and plug in inside the house until time to go home.
At home in UPS Mode a small lamp can be plugged in along with the medical equipment, and phone charging can be done as needed.
This might be great to allay power outage fears. Though there are tons of options, normal-use setup and operation is very simple.
If Gramps or Granny loves fiddling with tech, throw in a compatible 100 watt portable solar panel. Then they can geek out over options, as described here and elsewhere:
Bluetti UPS Modes Explained
And they are great for campers, drone hobbyists, digital photographers and videographers, etc.