To what extent is a Muslim obligated to apply the Qur'anic laws of inheritance, and what is the ruling if some family members do not adhere to the teachings of Islam (practically disbelievers)? Is the consent of all family members a prerequisite for applying these laws?

Nothing from the rulings of Allah falls away due to the change of time or place. The rulings of inheritance do not change, and Allah Almighty said after mentioning them: "An ordinance from Allah, and Allah is All-Knowing, All-Wise." Then He said: "These are the limits of Allah. And whoever obeys Allah and His Messenger—He will admit him to gardens beneath which rivers flow, abiding eternally therein; and that is the great attainment. But whoever disobeys Allah and His Messenger and transgresses His limits—He will admit him to a Fire, abiding eternally therein, and he will have a humiliating punishment." So, whoever abandons acting upon the inheritance laws has transgressed the limits of Allah. The knowledge of inheritance is half of knowledge, as some scholars have said, because all people are tested by it. If it is established that the one who abandons prayer is an apostate disbeliever—and this is the stronger opinion—then a Muslim does not inherit from a disbeliever, nor does a disbeliever inherit from a Muslim, based on the saying of the Prophet, peace be upon him: "A Muslim does not inherit from a disbeliever, nor does a disbeliever inherit from a Muslim." Therefore, those who abandon prayer do not inherit from those who establish it, and vice versa. It should be ascertained whether the abandonment of prayer is absolute, or if one prays some obligations and leaves others, for the disbeliever is he who abandons prayer entirely. Establishing the limits of Allah in inheritance is obligatory in all cases, and whoever does not accept the ruling of Allah is a disbeliever who does not inherit from his Muslim relative, nor does his Muslim relative inherit from him.