Awful situation I think she needs to continually hassle all and sundry - Council Officers, elected Councilliors, The Mayor, Housing Association (if applicable), Police (both locally and Force H.Q), MP, Euro MP.
Unfortunately this can happen to us all when lowlife move in. A friend lives in an expensive tree lined avenue of 1930's houses. Last year a broken, dysfunctional "family" of mother plus 3 scrotes were housed by DHSS in a privately rented house opposite. The predictable happened, noise, blaring music at all hours, revving cars, yobbos turning up and loafing outside etc etc. One of the 10 yr old kids goes to some sort of special school and the taxi plus helper woman would turn up every morning and wait 15 mins until the kid let himself out - no sign of the mother probably still in bed drugged up from the night before. As one would expect the uncurtained front room contained a Plasma TV big enough for my mate to watch from opposite. Thankfully for the residents they were moved on a month or so back to blight another part of town.