If he can, take a whole clove and break the ball and the prongs off the stem. Stick the stem between the problem tooth's gum area and check. Have him keep it there and it will relieve the pain.
Another old trick, although some people yell at me for saying so. Take a cotton swab and soak it in whiskey, and rub the swab on the problem area. The alcohol will numb the pain. Do not give him so much that he gets drunk though, so no shots. But the amount off the cotton is typically enough to numb it without getting him buzzed.