Tam's experience here mimics my own brief time behind the counter at a shop down here in Naples, Florida. Retirees would come into the store looking for a self-defense gun, but because of arthritis and other infirmities that go along with get old, they could not pull back the slide on most service 9mm's, nor pull the trigger on a double-action revolver.
I'd either point them in the direction of an LC-380, a Sig P238, (which, because it was metal to soak up recoil and seemed to be easier to work than other similar-sized locked-breech guns), or else I'd recommend the PMR-30 for the same reasons. Tam's had good luck with the Sig P250 in .380, and a revolver with a hammer than can be cocked is another option, but what else would you recommend to the ever-growing segments of our population who can't defend their lives physically, and so are looking to buy a firearm to even up the odds?