Sugar is a good source of carbohydrates which soil organisms thrive on. When I have a problem with my soil, I've used sugar to top dress the lawn. It's not a bad thing to do, but I wouldn't put the sugar (carbon) with fertilizer (probably way too high in nitrogen) together. It could heat up and destroy soil organisms, or burn roots.
I would say to stay away from his many ridiculous claims. They are not good recommendations for sustaining soils or biota. He is mostly interested in appearance of plants, not much in what's happening in the soil.
IMO of course.
V