My 13 yr old brother has ADHD too. Don't let his behaviour make you feel frustrated (although I know this is hard). He isn't doing the things he does out of naughtiness, he is doing them because of his condition. If your neighbours can't accept that he has this coindition and that is the way he is then it is their hard luck. There is a good chance he will grow out of this and whilst there is medication available, so long as he isnt a danger to himself or to others, there is no need for him to be on any.
You sound like a lovely compassionate person so just be sure to take regular breaks from him and allow the other members of your family some time off too. Sometimes there are days away or weekends that children with ADHD can go to for respie, it might be useful to talk to your gp (or his specialist) about this, or (and i know they get a lot of stick but they can help) social services.
Good luck

xx