Sorry, I humbly disagree. The way you stop bullying, (well at least the way we did it back in school) is to beat the bully within an inch of his life. It stops it in its tracks. And usually the other bullies will knock it off.
No more bullying and he will teach his kid not to bully.
Problem kids, like wild animals finding their way into human habitats, will be dealt with in similar ways, for similar reasons.