Complex sentence: In September 2016, he was reported to have been appointed as the minister of war of ISIL in place of Abu Omar al-Shishani; his appointment had not been announced by ISIL for fears that he might be targeted in airstrikes by the anti-ISIL coalition.
Split into simpler sentences: In September 2016, he was reported to have been appointed as the minister of war of ISIL in place of Abu Omar al-Shishani. However, his appointment was reportedly not announced by ISIL for fears that he might be targeted in airstrikes by the anti-ISIL coalition.