Advice on bad neighbours

A friend of mine is having some trouble with her neighbours. A couple of weeks ago she (politely) asked a local 11-year-old to turn down the music he was playing in his front garden, and received a mouthful in response. Ever since he’s taken to yelling foul abuse at her from his bedroom window whenever she leaves the house, and playing the music even louder whenever possible. His family recently kept half the close awake by having a midnight argument in their back garden involving such lovely phrases as ‘he wouldn’t be such an irresponsible f*cking c*nt if you weren’t such an irresponsible f*cking whore’, and my friend is justifiably worried that mentioning the problem to the boy’s parents would just make the situation worse.

Does anybody have any experience of this kind of situation? Should she stick it out until he gets bored, or do something more proactive?