Bees are not considered DOMESTIC live stock under the law as you would consider a dog, cow, or chicken DOMESTIC livestock. In other words as a function of law your neighbor is under no obligation to keep his bees confined on his property. Perhaps it would help if your attorney wrote him a letter that would jog the neighborly lobes of his brain. It also may not help. Like my granny said, "Honey, you can't make some people happy if you hung them with a brand new rope!"