Does the divorce issued by the father take effect with his statement, "Your sister is divorced three times if the marriage takes place," and is it permissible for him to take back his wife after the divorce has occurred, and is the sister's marriage valid despite the father's refusal after his initial approval?

The majority of scholars hold that a conditional divorce takes effect if the condition is met, regardless of whether the husband intended the divorce itself or intended a threat or prevention. They also hold that a divorce pronounced with the word "three" counts as three divorces. This is the predominant fatwa. Thus, upon the fulfillment of the condition, the mother becomes irrevocably divorced with three pronouncements, and she is not permissible for the father until she marries another husband.

However, according to Sheikh Al-Islam Ibn Taymiyyah, if the father did not intend to make the divorce conditional but rather intended prevention, then the divorce does not occur, and he owes an expiation for breaking an oath. If he did intend to make the divorce conditional, then only one divorce occurs.

Regarding the second question, the daughter's marriage is invalid as long as it is without the consent of her father, who is her guardian. The consent of the guardian is a condition for the validity of the marriage according to the majority of scholars, unless the guardian is unjustly withholding consent, in which case guardianship transfers to the judge. This marriage is to be annulled, whether before or after consummation, according to the majority of scholars. However, the Hanafis do not stipulate the guardian in marriage, and if a Hanafi judge were to rule this marriage valid, it would proceed, because the judge's ruling resolves disagreement.