Mao began to see his influence weakening so he began by setting up a power struggle. It was called the cultural revolution.
He believed the current governments in both the Soviet Union and China were placing too much emphasis on outstanding intellectual and engineering pursuits and not enough on ideological purity.
At the time of his death, 1.5 million people had been killed. The economy was in tatters and there was a 12% reduction in the population. That means that the 1.5 million really does not account for the 12% reduction in population.
He shut down the schools so that the main participants in this class war were students and the youth. They made life unbearable for the elderly. It disrupted the natural flow of the Chinese centuries old set of traditions where it was the duty of the young to care for the old.
Once Mao died, Chou en Lei took power and calmed things down. Mao was one of the monsters of world leaders to rule in the mid 20th century. He joins the ranks of Stalin and Hitler.