There is no spray that will get rid of mold that far along in flower that is safe to use. Remove all infected parts immediately and discard them. There really isn't anything else you can do once mold sets in. Don't even bother trying to wash that stuff. Consider it a loss. There are mold spores all over the rest of the plants and it will keep growing even after harvest while it's drying. One of the only reasons to harvest early is when you start getting mold. If you wait 2 weeks to harvest chances are you're going to find more mold as the days go by.
I've chucked entire plants in the past due to mold even though much of it looked fine. Upon closer examination of what looked like healthy mold free buds I found mold growth on the inside. It's not always obvious and some people will mistake the long thin mold which has a bulbous end for trichomes.
"Gray mold can be difficult to control because it has a wide host range and can survive for extended periods of time in the absence of a host as sclerotia. A single mode of prevention alone is unlikely to be successful in preventing gray mold.
Sanitation is an important component to preventing spread of gray mold. Clean all equipment used on/near plants. Removing dead and infected plants and plant parts is essential to preventing, slowing, and stopping the spread of infection. Avoid removing affected plant parts when the field is wet or humid to prevent the spread of spores in conditions that favor further infection. Proper spacing will promote air flow between and around plants, also reducing the risk of infection. Because
B. cinerea thrives in cool, moist environments, maintaining a properly watered environment with as little excess moisture as possible should reduce epidemics. Reduce humidity (below 50% RH) in greenhouses. Avoid over-fertilization to limit excess growth of the plant."
There are currently no effective, legal chemistries available to control gray mold in industrial hemp.