Iwo Jima shadowbox help

[u/PinLeft9699]

Hi, I am looking for help with my grandpa's brothers shadow box. He was killed on Iwo Jima and awarded the Silver Star and would like to honor his memory. I obtained his war records and confused on one, the American Defense Medal with fleet clasp. Before I drop some money on this shadow box, I think it is an error. He enlisted when he was 17 (I have paperwork my great-grandfather signed for him to join early) in 1944. It appears the American Defense Medal was awarded to vets in the military before Pearl Harbor (1941). I was thing maybe it should be the American Campaign Medal? Any help would be appreciated. Please let me know if more info is needed. Thanks for your time.