Depends on the laws of his locality.
Unless he was off in some country area, if he was within city limits, it's illegal to discharge a weapon.
The drone pilot may have been flying illegally as well "it was late evening And I would not be spying on her I’ll just leave it at that"
The pilot claims he was flying for commercial purposes, if he had the proper permissions I'm not sure why he wouldn't be getting any help.
As for it being over the person's house, this also depends on the laws in their locality.
Here in Virginia Beach, they only recently passed a law that if you pilot a drone over a person's house, and the property owner asks you to move it and you don't, it is considered a misdemeanor offense. This is due to privacy issues and not due to any implication that a property owner owns the airspace above their house, which simply isn't true.
If that were the case people could shoot at all manner of aircraft over their house. There are too many factors that aren't detailed in the OP to really go into whether or not it was 100% legal to shoot a drone down. My guess is no, mainly because in most places it isn't legal to discharge a weapon for the reason of shooting at a drone.