Not yet married but already thinking of divorce? When you think you've met the right muslima (halaal manner or course), perform istihkaara and make your decision. Rather than worrying about her removing the niqaab, spend that energy making dua for to remain steadfast in her deen insha'allah. We all have ups and downs in imaan during our lifetime. Help her raise her imaan again not shun her brother Thats just my opinion