He is also Second Secretary of the Politburo of the Central Committee of the Communist Party of Cuba ( PCC ) , Commander in Chief ( Maximum General ) of the Armed Forces ( Army , Navy , and Air Force ) and is the younger brother of Fidel Castro . The younger brother of Fidel Castro , he is also Second Secretary of the Political Bureau of the Central Committee of the Communist Party of Cuba ( PCC ) , and Commander in Chief of the Armed Forces ( Army , Navy , and Air Force ) .