Am I permitted to demand the return of the amounts I paid (Mahr and a sum to the wife's mother) while forfeiting the deferred Mahr, given the wife's health problems and her family's refusal to treat her or allow me access to her, and are they entitled to impose new conditions for her return?

If the wife is unable to engage in intercourse due to severe pain, she must seek treatment. Her refusal is impermissible because it harms the husband and deprives him of his legal rights. Her father is not permitted to demand impermissible conditions (such as money) in exchange for her treatment.

If she refuses treatment or if her recovery is impossible, the husband has the right to annul the marriage, because every defect that prevents the purpose of marriage establishes the option (of annulment), as Ibn al-Qayyim stated.

If she responds to treatment and recovers, there is no annulment. Defects in the private parts that prevent intercourse or its pleasure must be treated.

The option (of annulment) is also established due to a repulsive bad odor, unless it can be treated.

If the husband annuls the marriage, the wife must return the mahr because she concealed the defects. The correct view in the madhhab (definition) is that the husband returns with the mahr against whoever deceived him.

If the husband accepts the defect, his right to the option (of annulment) is waived, but his right to demand her treatment is not waived. If she refuses, she becomes nashiz (rebellious), and the husband may refuse to divorce her until she ransoms herself from him with money.