Complex sentence: This aspiration however, was not to materialize as Tusun died in 1816 (possibly of disease) and was then duly succeeded by his stepbrother and adopted brother Ibrahim in the role of chief military commander.
Split into simpler sentences: This aspiration however, was not to materialize, as Tusun died in 1816-possibly of disease. His stepbrother and adopted brother Ibrahim succeeded him in the role of chief military commander.