I have bought the pills for lactose intolerance and it does nothing for "sewage breath". I don't understand it. But when he cuts dairy out, his breath is sweet and he smells like soap. It is very hard for him to remember sometimes (especially with dishes made with cheese, etc.) ... but I instantly know if he eats anything with dairy ... smell comes back.
Give it a try. Eat absolutely no dairy for a day. Ask those who love you if the smell is gone. My husband cannot smell his own odor (which makes the situation even worse for the poor guy). But praise God we figured out what is doing it. It is a MOST embarrassing problem. I hope that this solves it for you too.