OP, do I feel for your wife. I have (osteo) arthritis of the hands and wrists as well as peripheral neuropathy. Thus, much of my hand strength and dexterity have gone South. As a result, I've done a lot of research into defensive handguns that will work for me.
I have good days and bad days with my hands, and I generally prefer/use revolvers over semiautos. Reloading a handgun for me is slow and messy, so I strongly prefer, and use the New York Reload - carrying and deploying a loaded 2nd handgun rather than reloading your primary handgun. My EDC is a Model 638-1 with a Model 38-0 both chambered in .38 Special, and I carry standard velocity ammo. Both are equipped with Crimson Trace LG-405 laser grips. The LG-405s have an air pocket along the backstop that compresses under recoil. If your wife can handle it, I recommend a Model 442/642 loaded with mid-range, standard velocity wadcutters. I'd apply a set of the Crimson Trace LG-405 grips, and might consider a spring kit to reduce the trigger pull weight.
For those times when my arthritis is really bothering me, I'll switch my EDC to a Model 432PD chambered in .32 H&R Magnum and a set of LaserMax laser sights. The back-up to my back-up is a Beretta Tom Cat chambered in .32ACP. The key advantages of the Model 432PD are that it's a six-shooter, and can safely chamber and fire any .32 caliber cartridge except for the big boys like the .327 Federal Magnum. Though it's no longer in production, it can be found on the Used market if you get lucky.
You'll find in a S&W J-frame revolver that the Centennial designed revolvers (Model 442/342, 432PD, etc.) have, out-of-the-box, the lightest/easiest trigger pull. Though they're not shooters, both my wife and daughter have remarked that the Centennial revolvers in my collection have the best and easiest trigger pulls than the non-Centennial design handguns.
The little Beretta 3032 Tom Cat is a bit bigger than you might believe. I've provided photos to try to give an idea of its size in comparison with the Model 432. The tip up barrel feature is nice. The magazine ejection is very brisk. The sights are terrible, but a laser grip is available as an option, and I have no problem putting 7 rounds quickly on target at 7 yards.
I hope this is useful to you. Best of luck to you and your wife.
Regards,
Dave