That's pretty much what you have to do, though. Step aside and let him hurt. I don't recommend watching. He has to learn to deal with strong emotions, sober. It was the hardest part of early sobriety for me. I didn't want to pick up a drink, but feeling all those feelings really sucked in the beginning.
I suggest finding something to do that gets you away from him while he works this through. If he drinks, it won't be because you did something wrong. He should be talking to a sober alcoholic about how he feels. When he gets tired enough of feeling miserable maybe he will start following suggestions.