Since you've determined that he's not an active 4 or 5 star general in the US Army, you can try putting various combinations of abbreviations of the other general ranks (BG,MG, and LTG) and his last name into google and see what pops up. If you can find his location or command out through conversation, that would be even better. Just to double check, did he specify that he is an active general in the US Army and not some other country's army? Like Nigeria? 😉