Are you not allowed to have roosters where you live? Being a good neighbor and not wanting to disturb them even if it's legal? Honestly, either way I'd suggest finding him a home where he can do what comes naturally and crow to his little chickens heart's content. I'd much rather do that than invest in a risky operation to make him stop. It's a lot of money, and I would rather have my chicken's best interest in mind than my own.
I (for all the good it'll do) am going to point out that said rooster already has a good home where he is allowed to carry out his rooster ethos to his little gizzard's content. I would (in my neighbor wife's presence) sternly suggest that said male neighbor stop watching my wife with his binoculars while she is Sun bathing. What was it that the good book said about water? OH.... I remember now..."into every life a little rain must fall." Well the same thing is even more true when it comes to female tears or else divorce papers. Maybe you'll get a new neighbor who loves chickens or at least fresh hen eggs.