You could also try some ground work - walk him in hand around outside of the barn and away from it. Get him used to other sights/sounds, where you are in a reassuring role on the ground. In the arena, work on "de-spooking" or desensitizing him. Bring in plastic bags, tarps, etc. and get him used to foreign objects.
Live, laugh, love.
My name is Lisa, and I am owned by Lucius and Sawyer.