What is the ruling of the Sharia on adding children to another person's passport for the purpose of emigration, and what are the ways to address this matter, given the perpetrator's ignorance of Sharia rulings?

Your father's act of adopting a child who is not his own is considered a lie and is not permissible except in cases of extreme necessity. If the adoption occurred due to a necessity (such as saving a life), then as soon as this necessity ceases, matters must be returned to their true state by returning the child to his real father and removing his name from the adopter's documents, even if this leads to his return to his own country. What is permissible due to necessity becomes invalid when the necessity ceases, especially since this matter can lead to the mixing and loss of lineages, which is forbidden. Therefore, his name must be immediately separated from the adoption documents.