I understand your concern, but there is quite honestly nothing you can do about it.
The girl's parents might perhaps have been able to do something when their daughter was little, and from what you say, they sought professional advice, which didn't help.
A thirteen year old is not going to change her ways right now, so all her parents can do is grin and bear it, unless they prefer and can afford to send her off to boarding school and wait with bated breath for the day when she is legally old enough for them to tell her to mend her manners or get out.
But to be honest, it is not the child's fault, but that of her parents who apparently have allowed her to behave like this.
It has nothing to do with when her mother went back to work, but everýthing to do with parents who either did not set boundaries, or did not work as a team when their daughter was little.
COUNTRY, CITY, AREA, PLACE -Game 21
Last weekend, in Rutland, the first statue in Britain of the late Elizabeth II was unveiled.