Because the linen is so thin and the embroidery is so old, I would use a backing of some kind (lightweight interfacing or a lightweight muslin, just make sure the stretch is going in the other direction from the scarf and stay away from any cut work or lace edges). You can leave it at that and put into a frame with glass over it, just make sure it's on acid free backing and mating and out of the direct sun). Or you if you have any other family items (ie: hankies, christening gowns, etc...), you could applaca them to quilt and then you it on a guest bed or as a wall hanging (using a pattern that might have been popular around your moms time or in colors she liked). Good luck and post pictures after your finished. Please