Getting custody of a child.

[Ihavereallyfuckedup]

My dsis wishes to live with me. Her upbringing has not been the best.
Social services are involved. For the moment she is staying with me. My mother has allowed a week.

After that she intends to force my dsis home. My dsis is vehemently against that. So where do I stand?

How old is she?

She is 13yo

I have spoke to social services and they are happy with my sister staying here a while. I am unsure what their reaction to residence will be though.