Joshua,
I can tell you about another club in Alabama that lost a flying site for this very reason you are talking about. they also ended up on Judge Judy when one of the planes crashed in the guy's yard. He sued them for the damage to his grass, and guess what he won. Of course that is TV justice, but there was some law behind it. I had heard from some of the people involved that the neighbor complained continuously about the people flying over his property and the AMA even got involved and tried to help in the ongoing fued. In the end I believe the club ended up having to move to a new site.
The best thing you can do in this situation is sit down and talk with this neighbor and find out why he has a problem with you guys flying there. Invite him out to fly with you. Heck if there are enough of you, chip in and get the guy a plane and have him join you. Unfortunately, your friend's rights to the airspace is not worth a hill of beans, and the neighbor is the squeaky wheel who will get his way. Don't let it get to the point of gunshots. Go to him and try to talk to him sensibly before it gets out of hand. I would be willing to bet you can salvage this situation.
Where are you located in Alabama? I'm in the NW corner, about 45 miles west of H'ville.
Tommy