So sorry for your loss. I say use them until they are falling apart. The two quilts made by my great-grandmother (in the late 40s) were falling apart and unusable. I took a good photo of each, took 2 square feet of the largest section in best condition and tossed. The 2 square feet wre bound with the binding taken from the quilt (another good section). Nobody in my family is going to care after I'm gone. I keep the sections for my sewing room (which is still dismantled, but hopefully will reappear by next Spring). Unless you are a preservationist, the fabric will just continue to deteriorate. Get good photos, professionally done if that is important to you, and then enjoy the work of your Mom.
It's no different for my own quilts. I will just make sure that family knows to select those that they will use and either donate the rest (children's hospital or social services for disabled adults) or auction them with the proceeds going to a local animal shelter.