Well, according to the strict rules, the answer is "No". These medals are, by regulation, for United States Merchant Marine personnel serving on U.S.-registered ships. I suspect there may be some "wiggle room", for example if his ship was technically chartered to the US government and became part of the US merchant marine fleet during this period, you might be able to make a case, but with the regulations reading "personnel of the U.S. Merchant Marine", I doubt you would be able to get anyone to agree that he was eligible.
Sorry for bad news.