Get a shooter's pack of springs for it from gunsprings.com < $20 shipped
Register at rugerforum.net and join in the discussion. Once you get the right number of posts you get access to Iowegan's IBOK on tuning the SP101. A couple of hours with some 2200 grit sandpaper polishing where he tells you and a swap to a lighter return spring and the mid weight hammer spring and you'll have a fantastic trigger.
Get her to dry fire it in the meantime. Even a lighter trigger is not going to compensate for that severe of a lack of strength in her trigger finger. She's not 80 and arthritic is she?
Gotta watch out for those dirty old ladies.