I have read several previous posts about just using the top and back with no batting for the same reason. You can surely do it and it will likely be perfect for him. What you will lose is the definition in your quilting design, because there won't be the thickness to allow for the difference in elevation around the stitching and the unstitched parts. But you can quilt it if you want rather than tie if that suits your look better. Many call these summer quilts.