How is inheritance calculated for the aforementioned heirs, taking into account debts, the deceased woman's will to build a water cooler, the son's dealings with his mother regarding the inheritance, whether the money one of the sons spent on her is considered a debt, and is it permissible for one of the daughters to waive her inheritance to build a charity well instead of paying zakat?

Before the inheritance is divided, the debts of the deceased, the Hajj on their behalf, expiations, and Zakat must be paid. If the inheritance is insufficient to cover the human debt and the right of Allah, then the jurists have differed on which of the two debts should be prioritized. Then, the will (water cooler) is executed, provided its value does not exceed one-third of the inheritance, and it is placed where she instructed. If digging a well is more beneficial, the will may be changed to that instead of purchasing the cooler. If the deceased left no heirs except their sons and daughters, then the inheritance is for them by way of ta'sib, with the male receiving the share of two females. The grandchildren (sons' and daughters' children) and siblings receive nothing and do not inherit when a son is present. A daughter who owes previous Zakat is not permitted to give voluntary charity before paying the obligatory Zakat. As for the rights mentioned between the son and his mother, scholars of knowledge should be consulted directly regarding them.