Fortunately, most of the damage was showing in the grassy area of the photo. That made it a little easier to clone in pixels from similar areas. There was relatively little damage to the little boy's face and clothing, which is always harder to repair. I overlaid a grid on the photo dividing it into 16 sections, and at high magnification, repaired one grid section at a time.
After the repair work to the damaged emulsion was done, I fiddled with the contrast to counteract the fading. All the tedious work is rewarded by the satisfaction of seeing the finished restoration, and another memory preserved.