Is the grandfather's approval required for a woman's marriage after her father's death, or can the eldest brother be her guardian (wali)? And is the mere presence of the guardian at the wedding ceremony, without explicitly stating approval, considered valid consent?

The jurists have mentioned an order for those with guardianship (wilayah) in marriage, and if the guardianship of someone entitled to it falls, it transfers to the next in line. The Hanafis, Shafi'is, and Hanbalis believe that the grandfather takes precedence over the brother, whereas the Malikis prioritize the brother over the grandfather. If guardians are equal in rank, such as brothers, and they differ on who should conduct the contract or who the groom should be, then the ruler (hakim) is the one who considers the matter and makes a choice. If the brothers entitled to guardianship agree on one of them, that is permissible; otherwise, the matter is referred to the judge (qadi). The mere presence of the guardian at the contracting session is not sufficient; rather, he must issue the offer (ijab). The guardian may also appoint as a proxy someone who meets the conditions of the guardian himself.