For his first level 1 Expedition, He chooses "after Expedition all Weapons +1". His first Expedition has now concluded. His Weapon strength goes up +1 because of his chosen Expedition reward (as do the Weapon strengths of any other Dwarfs in his following who currently have a weapon)
Is this true? We've always played where the extra +1 from the expedition reward only applies to the dwarf on the expedition.
If that's the case, I probably would have won quite a few more of my games with my adventure strategy.