Complaint will not be lodged unless your cousin sister countenances the allegations leveled by you in the complaint. Police will inevitably ask your cousin sister whether she supports the allegations made against her husband. If she says no, the complaint will be closed immediately. Your cousin sister has to muster the courage to come out of the closet and initiate the legal process by filing a complaint against her husband. No legal action can be taken against your cousin sister's husband unless she supports the allegations of harassment by him. On the contrary, you may be sued for defamation by him if your cousin sister does not acquiesce the complaint.