Sort of. It will kill most of it, but spores will go dormant or stay dormant until it's gone, then can proceed to attempt another attack once the sulfur is gone. Not bad to use as part of a combo.
You have such an extreme case of PM I doubt you will ever get rid of it with just neem and fans. PM is airbourne, its stuck to everything in your grow. You will also need to bleach or peroxide you entire grow: fans, equipment etc