Did any American or British soldiers get awarded the Iron Cross whether serving on the side of the Germans or not?

My Grandfather Capt. Wolfgang Fleck was awarded the Iron Cross at the age of 14 for destroying 2 U.S. Tanks with a panzerfaust. After the majority of his unit was destroyed in 1945 he was captured by US Army units who instead of killing him decided he was too young to die at the age of 14 or 15. In 1952, He went to America to join the US Marines where he served as a Motor T Driver in Korea where he lost multiple trucks to enemy fire. He stayed in the Corps Becoming a Pathfinder & US Marine force Recon: He completed OCS then became a DI training thousands of marines for Vietnam. He later went to Vietnam to work intelligence in the field and was a very effective interrogator. He was allowed to wear his Iron Cross on his uniform and was given special dispensation to do so.