Does an adopted son inherit, and does he disinherit the grandchildren of the deceased from inheritance if there are a grandson, a granddaughter, and two granddaughters of a son?

An adopted person does not inherit from their adoptive parent because that person is not their biological father. Adoption, where a child is ascribed to the lineage of the adoptive parent, is forbidden (haram (definition)). If a woman dies leaving behind a daughter, a grandson (son of her son), and two granddaughters (daughters of her son), and no other heirs, then her daughter receives half of the inheritance as a prescribed share (fard), according to Allah’s saying: "And if there is only one, she will have half." The remaining portion goes to the grandson and the two granddaughters by way of residuary inheritance ('asabah), with the male receiving the equivalent of the share of two females, according to Allah’s saying: "Allah instructs you concerning your children: for the male, what is equal to the share of two females." Thus, the inheritance is divided into eight shares: the daughter receives half, which is four shares; the grandson receives two shares; and each granddaughter receives one share.