The 104th Field Artillery Battalion (formerly 2d Battalion, 104th Field Artillery) was an element of the 27th Infantry Division. It appears the battalion was in the New Hebrides in January '45, preparing for the Campaign in the Ryukus (Okinawa, etc.). The Bronze Star is awarded for non-combat as well as combat action. Perhaps he was cited for valor during a training exercise or something of that nature. You'd have to access the battalion's operational records for a precise answer - and may find nothing even there. Remember, many of the records you seek don't exist and many of those never have!