I think it's a nice capture and a couple of things that might have made it even nicer would have been to zoom out slightly so that you weren't cropping off bits of limb, and to attract the child's attention so that he was looking towards the camera. I might also consider taking this back to the pixel room and seeing if a little more detail could be pulled from the gentleman's right eye area.
I really like the "Americana" feel of the photo. I wish the little boy would be looking at you or his pap...but any picture with a grandparent is a treasure to be kept.