It is an unfortunate circumstance that you had planted these trees and your neighbor chose that day to spray the 24D. This spray can cause the curled and dead leaves that you're describing. This particular spray can easily dissipate as a vapor in warm and windy conditions. The good news is that your tree can recover from this, but there isn't anything to hasten the process. Next year you should have normal-looking leaves. In the mean time, make sure your trees are watered regularly and add a mild tree fertilizer to help minimize the stress to your trees.
Ask your neighbor to let you know when they're going to do this again and let them know not to do it in hot and windy conditions!