What is the share of each heir from the deceased's inheritance, is Zakat obligatory on an undivided inheritance, and is it permissible to give Zakat to a married sister?

The will must be executed before the division of the inheritance. If the amount bequeathed for building a mosque does not exceed one-third of the inheritance, it must be fulfilled, as the Prophet, peace and blessings be upon him, said: "Indeed, Allah has bestowed upon you one-third of your wealth at the time of your death as an increase in your good deeds." If it exceeds one-third, only the one-third must be fulfilled, and anything beyond that depends on the consent of the adult and mature heirs.

Regarding the heirs, the wife receives one-eighth due to the presence of a direct descendant, and the remaining is for the sons and daughters by ta'sib (residuary heirship), with the male receiving the share of two females. There is nothing for the other mentioned heirs as they are excluded by the sons. The inheritance is divided into 120 shares: the wife receives 15 shares, each son receives 14 shares, and each daughter receives 7 shares.

Heirs may not be prevented from their right to the inheritance. In the case of minors, their guardians or the judge shall handle their affairs.

As for zakat (definition), it is not obligatory on the total amount of wealth, but rather on the share of each heir if it reaches the nisab (definition) (minimum threshold) and a full year has passed since its ownership. It is permissible to give zakat to the sister if she is poor and not sufficiently provided for by her husband's maintenance.