I would tell her about how there's no way to save all of the quilt and give her the options. Either you take it apart and use what you can, or you make her a new one with good fabrics. She doesn't have to throw out the old one, can't it become a cat blanket? I mean, my kitties love it when they get to snuggle on my quilts. You could even make that a suggestion, after remaking her quilt with quality fabrics, you could make cat beds out of what you can from the old quilt!