I think it would help to have a little more information. The picture you posted is kinda blurry, so it is hard to impossible to read the details. I can see that the top part of the paper says something-"creek". I cannot read its name, but your friend might be able to gather information by looking up the locations on Google Maps.

Does your friend now what part of the forces his grandfather was a part of or when this was taking place / where he was stationed? At least some information what country your friend's grandfather served for would be helpful, so historians who have researched that specific country's involvement in WW2 could have a look at it.