Is she entitled to inheritance if they were divorced via the court?

My brother passed away. He had two sons and was divorced. My mother is still alive. The following problem has resulted after my brother’s death.His –ex-wife claims they were only divorced from a western perspective and my brother did not issue taalaq. The divorce proceedings in the courts were initiated by his ex-wife. Originally my brother opposed the divorce in the court, however he subsequently changed his mind and agreed to the divorce. He signed the necessary papers and also abided by the divorce order. He gave his ex-wife half the house and agreed to pay maintenance for the children. My brother and his wife have not been living together for at least ten years.The question is, are they divorced from an Islamic perspective?