I made a "summer" quilt for my bed and I only used a thin fleecy blanket as the backing. When I showed it at quilt guild and told them what I did everyone got excited and said they had never thought of making a summer quilt in that manner. As it turns out the quilt is still too warm when it's 100 degrees here BUT I can always turn it back and sleep with just the sheet. I put it together pillow case style so no binding was needed and it was thin enough on the edges so that all I did was stitch about a 1/2" all around to keep the edge from rolling. For added fun I machine embroidered butterflies randomly on the top to make it look more like a traditional quilt.
Tell your family when they make their quilt they can make it anyway they want. It's called creativity.