Daniel - I, myself am not clear on this, but could it be that you are not "next of kin"? I have forgotten the exact definition but I remember reading it in the NPRC section of NARA.
I have had much trouble with that branch with my husband's records. My last effort was by letter since I knew they did not look up the info I wanted by using the "form". I also knew that their branch was where such info was stored if it was available.The reply was to send me the form to fill out with the soldiers name listed as mine! You figure. But put NARA in your seach line and go from there. Others on this site are much more informed than I so you may hear from them, too. Mary