How is an inheritance distributed among: one son, a father, three full brothers, a husband, a mother, and two full sisters?

If the deceased left behind only a mother, a father, a husband, and a son, then her mother receives one-sixth, and her father receives one-sixth, due to the presence of a lineal descendant (heir in the descending line). Her husband receives one-fourth, also due to the presence of a lineal descendant. The remainder goes to her son by ta’sib (residuary inheritance). The full sisters and full brothers receive nothing, as they do not inherit in the presence of a son or a father. The inheritance is divided into twelve shares: two shares for the mother, two shares for the father, three shares for the husband, and five shares for the son.