Instead of messing with the gun, she could try the isometric method of operating the slide.
It goes like this:
She holds the gun up close to the body, strong hand and gun in line with her shoulder, elbow bent and pointing down.
The support hand goes over the top of the slide, with the thumb pointing back at herself.
With one smooth motion, the support hand pushes back on the slide, and, at the very same time, the gun hand pushes forward, using shoulder and arm strength to aid.
Betcha' she can do it with ease.