As per Muslim Law divorce can be get by two process one is Judicial and other is Extra Judicial. If your brother not dezire to continue this marriage then he can seek divorce . I suggest you that send one legal notice first and mention in it that how they get married and what issues in between them going on and ask her or tell her for mediation in which 3 persons from your brother side and 3 persons from his wife side will conduct meeting. ak for the place and date of meeting or tell as per convinience of both. Then discuss the issues in meeting if both the parties are ready then its well and good as talaq can be get mutually but if not then send first notice to her and mention in it that as we conducted meeting and it get failed so i pronounce you talaq and send iddat amount with that notice . Follow the procedure three times provided she should not be in Menstruation Period. For ferther detail you can consult .
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