Can my sister at the age 15 live with me if home life is unstable

I am an attorney in FL not NC but I suspect that the analysis will be parallel. You should seek an guardianship proceedings generally require such expert advice. The natural parent's rights (the father's rights) would have to be taken away for you to have a superior right to care for the child. Have you attempted to discuss this with your father to see if she might just allow her to go with you rather than employing the courts to force this to happen. If, however, there are some other assets that her mother left, you may be able to seek guardianship of the property. This may be an issue you can attack from an indirect perspective. If you are the guardian of the property and control the assets, your father may be more willing to acquiesce with the custody issue for your sister.

I'm not a family law attorney, but it may be possible to obtain custody of your sister. My advice to you is to hire a competent family law attorney. This is not a simple matter, and it sounds like you want what's best for your sister. Honestly the best advice I can give you is to hire an attorney in your area who can help you out.