Total Army Personnel Command ATTN:TAPC-PED-F Alexandria, VA 22231-0482
When writing request the IDPF and give them the Name, Branch of service ( in this case US Army ) , and Sevice number. This information is needed at a minimum . If you need his service number looked up I can do that for you.
Make sure when you make the request you state that you are a relative. I ussually use the Freedom of information act to make my requests for non-relatives.