Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first.
Where is the father of the child and have Social Services been involved at all?
Has your neice spoken to school about her problems?
Will her mother object to her moving to your care
What abuse has she suffered?
How old is the younger sister and do you have any concerns for her care?
If you wish your niece to come into your care she needs to tell someone what is happening to her.
This could be a trusted Teacher at school, or even Childline.
Alternatively you could speak to Social Services.
At that point you could ask that she stays with you whilst matters are investigated further
At 13 her wishes will be seen as inportant and it is likely that Social Services will agree with this.
Once matters have begun then you can apply for a Child Arrangement Order stating that she lives with you
Please ask if you need further details
You are very welcome - I hope all goes well