Although they require some different safety habits to learn, couple of the ways that work for the ladies are to:
Hold the gun parallel to the body and push the frame and slide in opposite directions. She might be able to use the palm of the bad hand as well as thumb and fingers.
Other way is to use the bad hand to hold frame and good hand to hold slide. Push-pull would work this way. Few extra seconds to switch back, but little practice would minimize time factor.
Other thing that comes to mind would be a slide racker as on scoped units, designed or modified for her use. Along same lines, adaptation of a scopemount or part thereof to the slide.
Dependent upon intended usage, a lot of the gals seem to prefer a single action revolver.
Some like the grip, some the balance, some both, some the simplicity.