Castro never stepped down and handed over the reins of power. Pinochet did.
He will soon.
However, it will probably be involuntary and due to his assuming room temperature.
And the level of human rights violations, based on number of deaths, is two orders of magnitude lower for Pinochet than for Castro, if I remember my Rummel correctly.
This does not begin to take account of the higher level of human misery due to needless communist-imposed poverty in Cuba.