Steel rim? Now there's a novel solution.
ever try to bend a steel rim without spoke and a hub,I tried couldnt,i also tried to bend the aluminum rim of my trek cc when I replaced the wheel,yes it bent.
What choice does he have,he will either keep popping spokes or have to get a new wheel,20 radial spokes will not support his weight,sheldon brown has something to do on his site about spoke count and radial spoking.