Complex sentence: He breaks down into tears and recounts the events the day of the attack and the last thing he said to his wife before their death: they had argument about remodeling the kitchen, which is why he compulsively remodels it every few months.
Split into simpler sentences: He breaks down into tears and recounts the events the day of the attack. Later, he mentions the last thing he said to his wife before their death: they had argument about remodeling the kitchen, which is why he compulsively remodels it every few months.