Caliph Ma'ad al - Mustansir Billah died soon afterwards .
Al - Afdal appointed as caliph al - Musta'li , a child , instead of al - Mustali 's much older brother Nizar .
Caliph Ma'ad al - Mustansir Billah died soon afterwards , and al - Afdal appointed as caliph al - Musta'li , a child , instead of al - Mustali 's much older brother Nizar .