I would survey the cemetery for the number of unmarked graves near his buried family members. If it is a very small number that will give you a starting point. Then start on eliminating that number down by looking at the dates on the stones. Look for a date of a family member that died about the time your subject died, that also has an unmarked grave next to it. But keep checking for a paper trail. I would go ahead with procuring the VA headstone and place it at an unmarked grave next to one of his family members. This could be temporary until you find his exact grave site, then move it, but you could be lucky and get the right site. At least he would have a headstone to be remembered by. When I have placed Veteran's headstones, I have gotten permission from the cemetery's offical and did the job myself.