Texas Family Code - FAM § 162.507. Effect of Adoption

(a) The adopted adult is the son or daughter of the adoptive parents for all purposes.

(b) The adopted adult is entitled to inherit from and through the adopted adult's adoptive parents as though the adopted adult were the biological child of the adoptive parents.

(c) The adopted adult may not inherit from or through the adult's biological parent. A biological parent may not inherit from or through an adopted adult.