Since I can't see how and where the fraying is it's hard to tell what her outcome will be. From my experience, all fabric frays to some extent. The more you have to work with a piece stacking, placing it with another piece, sewing and unfortunately, sometimes ripping and resewing you are going to get some fraying. I leave all the frays in place as much as possible to hopefully get a more accurate quarter inch seam. I clip all of them when I do the final pressing of the quilt top. Some fabrics fray more than others and that maybe because although they are all cotton they may not have the same thread count. Looser weaves will have more fraying most generally.