Is my friend considered sinful and held accountable if two false witnesses testify on her behalf in an eviction case, whether with her knowledge or without it, and what is the expiation for that?

If the sister has no legal right to reside in the property, then she is not permitted to remain there without the owner's consent, for a judicial ruling does not make lawful what is unlawful, nor does it make unlawful what is lawful. However, if she does have a legal right but cannot obtain it except through false testimony or bribery, then some scholars have permitted it, but refraining from it is safer. Therefore, it is advised to withdraw the papers from the lawyer unless she is in dire need and has a legal right. If someone testifies falsely without her knowledge, there is no sin upon her. It is recommended to involve righteous people to mediate with the property owner and remind him of the virtue of making things easy for those in hardship.