Nobody but another quilter will ever notice, I promise you! I grew up with my grandmother's quilts and always thought she and her quilts were perfect. Then became a quilter and started really studying them and discovered to my surprise that HER blocks don't quite line up sometimes either and I never, ever noticed! I've owned some of these quilts nearly my whole life and I treasure them all. My husband & I use one of her quilts on our bed that she made for me when I was 16, even though it's too small for the bed. It's the coziest quilt we own and he loves it almost as much as I do - we wrestle over it all the time, LOL.
Your son will love that quilt forever.