You might want to order his deceased file. You'll find practical instructions at Message #2112. Go back to the main page, enter "2112" in the box in the upper right corner labeled, "Jump to #_____" and click on "Go".
You'll also find a link on that page that will take you to the ABMC-sponsored overseas cemetery directory search website. Double-click on the linkand follow directions to your uncle's place of interment.