All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the conditions and pillars of marriage are fulfilled in a marriage, then it is valid and it takes effect even if it is not registered. Registration is but an additional matter in order to preserve the rights and it has nothing to do with the essence of the marriage contract. For more benefit on the conditions of a valid marriage, please refer to Fatwa 83629.
Moreover, it is not permissible for a wife to ask her husband for Khul’ without a sound reason. If such a reason exists, then it is desirable for her husband to accept her request.
Khul’ has its conditions so that it becomes valid among which is that it should be in return for a compensation upon which both parties agree. For more benefit, please refer to Fatwa 122890.
In principle, Khul’ should be with the consent of both parties but sometimes it may not meet this principle like when it is not possible to reconcile between the two parties, in which case, the arbitrators may separate between them according to some details which the scholars mentioned. Also, the Islamic judge may rule divorce against the will of the husband in some cases.
As regards the authority which you mentioned in the question and which ruled Khul’ as you mentioned, then if it is a reliable Islamic authority, then in principle, it should not rule Khul’ unless it finds what necessitates it and unless it was appointed by the judge to act on his behalf or that it is in a country where there is no judge. So, we advise your brother to consult this authority and investigate its reality.
Allaah Knows best.