Complex sentence: Muhammad Taha died around 1920, leaving his four children to be brought up by their aunt in Rufa'a who also had them go to school, and Mahmoud completed the extremely competitive educational system of the time.
Split into simpler sentences: Muhammad Taha died around 1920, leaving his four children to be brought up by their aunt in Rufa'a who also had them go to school. Al-Ustaz Mahmoud was able to complete the extremely competitive educational system of the time.