Where I live, this would not work well. There is very little FRS/GMRS communications around here when I’ve been listening for it.

Most FRS/GMRS radios are terrible; they have tiny little fixed antennas and grossly inflated claims of range. The best of that lot are actually good for somewhere between 1/4 mile and maybe five miles, in most environments. Peak to peak, you might do better. But with those awful antennas, you might not.

Could your elderly friend get a ham radio license? I have hit repeaters that were 50 miles away using a J-pole hung up high with a portable VHF rig; HF can get you far further but requires more gear and expertise. It’s easy to find hams to talk to on the radio, and when regular telephony and Internet goes down, it will be much easier still.

If that’s not an option, perhaps your elderly friend could organize a FRS net with a few nearby neighbors?

Without ham radio or nearby neighbors willing to participate, I think Blast’s idea of setting up ones own GMRS repeater with hardened power and encouraging others around to use it is the best bet.