Vowing not to marry her daughter until she is 20 if she is cured from her disease

Q: My daughter who lives in Al-Qasim suffered from a severe illness at the age of four, and her mother pitied her immensely. Now, my daughter is 17 years old, and her mother vowed not to gave her in marriage to anyone until she is twenty if Allah cures her of her illness. My daughter's marriage contract was concluded, but we laid a condition on her husband not to consummate the marriage until she attains the age of twenty. My daughter does not mind the consummation of her marriage now, but she takes her mother's vow into consideration and does not want to overburden her. Currently, she gets seriously ill and this disturbs us very much. People advise us to conclude her marriage that will help improve her condition. When we asked about the Kaffarah of her mother, it was said that she has to expiate for breaking her vow by feeding sixty needy people or fasting for two consecutive months. Please, advise us in this regard. May Allah reward you with the best!

A: If the case is as you have mentioned, it is preferable that the marriage of your daughter is consummated (Part No. 23; Page No. 217) even if she has not attained the age of twenty in order to alleviate hardship from her parents. The mother of the daughter has to offer a Kaffarah (expiation) of breaking an oath by feeding ten Miskins (needy people) with five Sa`s (1 Sa` = 2.172 kg) of wheat, dates, rice or the like to be equally distributed among them. Optionally, she may provide the same number of Miskins instead of feeding them. If she is unable to do so, she may move to the next option, which is to free a believing slave. If she still cannot afford any of these alternatives, she must fast for three days preferably, on a consecutive basis. Allah (Exalted be He) says, Allâh will not punish you for what is unintentional in your oaths, but He will punish you for your deliberate oaths; for its expiation feed ten Masâkîn (poor persons), on a scale of the average of that with which you feed your own families, or clothe them or manumit a slave. But whosoever cannot afford (that), then he should fast for three days. That is the expiation for the oaths when you have sworn. And protect your oaths (i.e. do not swear much). The vow of the mother takes the same ruling as the oath.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.