Sounds to me like he didn't follow the label requirements, with spraying on a windy day. If that is the case, he is liable for any damages and expenses incurred as a result. Find out what he sprayed first, and leave it at that for the moment. Then read the label requirements (online) and if he violated them, print them and show them to him. Explain to him about your exposure, and the loss of the bees and ask him how HE feels it should be handled. Then, if you are satisfied, you may have a new ally. If you are not satisfied with his response, call your lawyer!