Complex sentence: John McCoy was Adjutant General for the division; after he was shot and captured by British Crown forces in 1921 Sean F. Quinn, Padraig's brother, took over the position.
Split into simpler sentences: John McCoy was Adjutant General for the division. After McCoy was shot and captured by British Crown forces in 1921, Seán F. Quinn, Padraig's brother, took over the position.