The spring will loosen up after some rounds, but IMO the difference is negligible.
As Dfariswheel stated, a lighter spring in that pistol would not be advisable.
Has she tried grip strengthening exercises?
I have the CC model and it is quite stiff, took some practice to get accustomed to racking the slide on such a small frame.
"The best diplomat I know is a fully charged phaser bank" - Montgomery Scott