If the adopted child knows of the impermissibility of changing his name and wants his share of the inheritance, is it permissible for the heirs to reluctantly divide the inheritance with him if they cannot prove in court that he is adopted? And is it permissible for the adopted child to keep his adoptive father's name to avoid harm that might befall his children (such as suicide) if they learn of his true identity, provided that he takes nothing from the inheritance?

The adopted child is not entitled to inherit anything from the one who adopted him, as there is no legal cause for inheritance such as kinship, marriage, or wala’ (allegiance). Whatever he takes from the inheritance is unlawful, even if a judge rules in his favor. If the adopted person is unable to change his name, he must write a document and have it witnessed, stating that he is not the son of the one who adopted him, and this should be made known within the family to avoid falling into what is religiously forbidden.