Two executors — may one act alone?

Neither may act alone. The deceased entrusted the matter to the two of them jointly and did not accept the judgment of either on his own, so an act by one is ineffective without the other — the same rule as for two agents appointed together. In the Maliki school the exception is an express term in the will or a clear indication that separate action was intended; in the Hanbali school an express term. Where one of the two dies or cannot be reached, the judge appoints a trustworthy person to stand in the missing one’s place.

Sources: al-Fiqh ‘ala al-Madhahib al-Arba‘a, vol. 3, “Mabhath al-wasi al-mukhtar” (the chosen executor), school by school (‘Abd al-Rahman al-Jaziri (d. 1360 AH)) · al-Mughni, Kitab al-Wasaya, fasl 4773: “fi man tasihhu’l-wasiyyatu ilayhi wa man la tasihh” (who may be appointed wasi) (Ibn Qudama al-Maqdisi (d. 620 AH)) — all three separately stated in al-Jaziri; Malik and al-Shafi’i separately named in al-Mughni, which states the Hanbali rule as its own.

Not generally — but there is a list of exceptions. The school carries two views, and the one most of its scholars endorse is that neither executor may act alone. Against the strict analogy, however, Abu Hanifa and Muhammad al-Shaybani allow either of them to act singly in a defined set of urgent matters — shrouding and burying the deceased, paying his debt, carrying out his bequest, returning a deposit to its owner, buying a child’s food and clothing, accepting a gift on the child’s behalf, selling what will spoil, and litigating on the estate’s behalf — because insisting on both signatures for these would be onerous and delay would do harm. Abu Yusuf went further and allowed either to act alone throughout.

Sources: al-Fiqh ‘ala al-Madhahib al-Arba‘a, vol. 3, “Mabhath al-wasi al-mukhtar” (the chosen executor), school by school (‘Abd al-Rahman al-Jaziri (d. 1360 AH)) · al-Mughni, Kitab al-Wasaya, fasl 4773: “fi man tasihhu’l-wasiyyatu ilayhi wa man la tasihh” (who may be appointed wasi) (Ibn Qudama al-Maqdisi (d. 620 AH)) — the two Hanafi views and the list of urgent matters in al-Jaziri; Abu Hanifa, Muhammad and Abu Yusuf separately named in al-Mughni, which gives the seven-item version of the list.