How is an inheritance divided among a mother, two sons, and three daughters? Is it permissible to treat an addicted son from his inheritance? Should he be given his money despite his squandering it on drugs?

If your brother is a profligate (safih), a guardianship should be imposed on him for his own benefit. If he is a minor or reached maturity as a profligate, his share of the inheritance should be given to his guardian or custodian, and it is permissible to spend his share on his treatment. However, if he became profligate after reaching maturity and sound judgment, then, according to the majority of jurists, a guardianship over him requires a ruling from a Sharia (definition) court. Muhammad ibn al-Hasan (definition) and Ibn al-Qasim, however, hold the view that guardianship does not require a judge's ruling. Therefore, the matter should be brought before the judiciary, and if that is not possible, the relatives should undertake the guardianship until he regains sound judgment. Regarding the division of the inheritance, if the mother mentioned is the mother of the deceased, she receives one-sixth due to the presence of a descendant heir. The remaining portion is for the sons and daughters by ta'sib (residuary heirship), with the male receiving the share of two females. The estate is divided into 42 shares: 7 for the mother, 10 for each son, and 5 for each daughter. However, if the mother mentioned is the wife of the deceased, the estate is divided into 8 parts: one share for the wife, one share for each daughter, and two shares for each son. It is obligatory to refer inheritance matters to Sharia courts for investigation into them, as well as to ascertain the presence of wills, debts, or other rights that take precedence over the heirs' rights.