How can I get my sister out of sin and bring her back home? Thank you.

The following is recommended for your sister's righteousness:

1. Frequent supplication for her, especially during times when prayers are answered. 2. Persistently advise her with gentleness and wisdom, and warn her against sins. 3. Refer the matter to her guardian or one of her relatives who can influence her. 4. Shunning her if there is benefit in it.