Is a sister's marriage valid after her khulʿ divorce and the expiration of her waiting period, if it takes place without her family's knowledge, and what should the family do regarding her and her new husband if the marriage is valid?

The majority of jurists hold that the guardian (wali) is a condition for the validity of marriage. Therefore, if a woman marries herself without the permission of her guardian, her marriage is invalid, and they must renew the contract with the guardian's permission and the presence of witnesses. This is unless a Shariah judge, who does not consider the guardian a condition, rules their marriage valid, in which case the marriage proceeds. If the marriage is valid, no one is permitted to interfere with them, and the family must fear Allah and avoid severing ties of kinship.