His deceased file will contain information of interest or use; should contain the exact location of his death (or disappearance). You'll find instructions on how to request his file at minimum expense (about thirty cents) at Message #2112.
(NMI) = "(No Middle Initial)". This is "bureaucratese" and means simply that he was known only as "Wilford Moncus" to the army. You need not include this in your request. In fact, per the instructions referred to, simply state, "I would like a copy of the IDPF of Wilford Moncus, 34 973 641, who died 21 January 1945."
Keep it simple. The employees who process these requests do so on a routine, daily basis and know their job. You can likewise delete "USA" from the PERSCOM address (the example given was recently posted at another message to an individual in another country).