Is the mother's approval of her daughter's engagement considered valid, and is that sufficient for the completion of the engagement, or must the father's approval be obtained?

The mother has no authority to marry off her daughter; rather, the authority belongs to the male agnates (asabat). The engagement does not require the involvement of a guardian (wali), and it is permissible for a man to propose to a mature, sensible woman directly. The validity of the engagement depends on the acceptance of the mature, sensible woman if she is not coerced, and on the acceptance of the guardian if she is coerced. The preponderant opinion is that a mature, sane woman cannot be coerced into marriage. The engagement is merely a promise of marriage, and the suitor remains a stranger to his fiancée until the marriage contract is concluded.