I have to ask how the wife knows she cannot rack the slide when you do not have a complete pistol. Pistols can be racked several ways/methods. The push-pull generally works for almost anyone who may suffer hand/arm strength.
You do not have to grip the slide to use the push-pull method. Simply allowing your weak hand to firmly rest on the slide, the grip hand pushes the pistol forward and just the friction/weight of hand will hold the slide while the other arm and hand push the entire pistol forward. Adding a device to the slide is a fools errand and dangerous.
You are not shooting a competition weapon. If she can do it with that device attached she can do the push-pull method better and safer. You do not have to squeeze the blood out of the slide. I can firmly lay my hand on the slide, not squeezing and push the pistol into battery with my strong hand and generally use this method over the "grasp" the slide.
If her hands and arms are that weak a double action revolver is not going to solve your problem as the average trigger pull begins around 12lbs, some as high as 18lbs.
Solution, you make pistol ready and place in safe place with a few extra magazines.
All she has to do is retrieve pistol.......pull trigger, if the pistol is shot dry-eject magazine-insert new one and hit the slide release-round is loaded for next shot string.
You do both need training since this seems to be a complicated situation for both of you. Good luck.