What is the ruling on a man attributing his wife’s granddaughter to himself and registering her as his daughter in official records, and purchasing properties and registering them in the name of the heirs, including the aforementioned daughter, to the exclusion of three of his male sons?

Adoption is a pre-Islamic (Jahiliyya) practice that is forbidden. It is not permissible for a man to adopt his wife's granddaughter and attribute her lineage to himself. The adopted girl does not inherit from the adopter, and registering her among the heirs is a grave error that infringes upon the rights of the original heirs. However, a man can bequeath a portion of his wealth to her, provided it does not exceed one-third of the estate.