Must the heirs of a deceased man carry out his will to sell his car and donate its price as charity, knowing that his family is in need of this money?

Bequests are legislated by the Qur’an, Sunnah (definition), and scholarly consensus. They are valid only within the limit of one-third of the wealth. More than that is not permissible unless approved by the adult heirs, because the Prophet, peace and blessings be upon him, said: "It is better for you to leave your heirs wealthy than to leave them poor, begging from people." Bequeathing more than one-third is considered an impermissible harm.