Is it permissible for a brother to contract a souria marriage with the wife of his missing brother in order to register her daughter who lacks identification papers, and then divorce her afterward?

If it is possible to wait for the brother's return to register his daughter in his name, then that is the obligation. However, if it is highly probable that he will not return, and it is not possible to register the girl in his name, then a 'sham' marriage is permissible, provided that the pronouncements of offer and acceptance are not uttered. It suffices to write this in the documents so that the girl is attributed to the questioner, while spreading the word that she is his brother's daughter to mitigate the repercussions of this attribution as much as possible. This action is considered committing the lesser of two evils, as the loss of the girl's lineage is a greater harm.