Probably the simplest solution, but since this guy will not even tell OP what award he got then I very much doubt he will show his records. I know his type and it is always a sad thing to see, some guy that had it rough in the Military and just cannot cope in civvy street, they will make up fantasies and stories to impress others and will often go to great lengths to cover up their fibs. Often they will even purchase awards and kit from ebay and try to pass it off as proof of their exploits.
The best way to catch out one of these imposters is to ask what units they served with, the more elite or prestigious they are the more they should be viewed with suspicion. You will rarely catch a Walter Mitty posing as a vehicle mechanic or clerk, they are always elite units or regular units that have undergone some sort of special training such as sniper school.