Denim lends it self well to a rag quilt. I've made one with denim on one side and flannelette on the other. Depending on where you live I don't think it's necessary to use batting. Increase the seam size to 1/2 inac, or 3/4 inch. It will last forever. The hardest part of the quilt is cutting up the jeans, it's a big job. In my own humble opinion this is what quilting is all about. If you were close to her this could also be very therapeutic. If you've never made a rag quilt before I suggest you give it a go. You won't be disappointed.