What is the ruling of Islamic law regarding an unregistered will that heirs demand years after the testator's death, and does the one who concealed the will bear a sin?

A man's will to distribute inheritance among sons but not daughters is legally void and contrary to the words of Allah Almighty: ﴿Allah instructs you concerning your children: for the male, what is equal to the share of two females﴾.

Furthermore, it is a bequest to an heir, which is not enforceable without the consent of the other heirs.

This will must be rectified to conform with Islamic law, based on the words of Allah Almighty: ﴿But if one fears from the testator some error or sin, and he makes peace between them, there is no sin upon him. Indeed, Allah is Forgiving and Merciful﴾. Thus, rectifying a will means replacing any error or sin within it for a benefit, and there is no sin upon the one who rectifies it.

The Sunnah for greeting a Muslim is to say: "As-salamu alaykum wa rahmatullahi wa barakatuh" (Peace be upon you, and the mercy of Allah and His blessings). As for "Salamun ‘ala mani ittaba‘al-huda" (Peace be upon whoever follows the guidance), it is said to a disbeliever.