Fidel Castro recruited former members of the Nazi SS Waffen to train his troops at the height of the Cuban missile crisis.

This is confirmed in declassified German intelligence files show.
Papers released this week by the BND – the German foreign intelligence agency – reveal that Castro personally approved a plan to hire former Nazi officers to instruct the Cuban army.
Papers dating from October 1962 show that four former officers from the Nazi death squads had been invited to Havana.
Source: Telegraph.co.uk
My comment:
It is important to acknowledge that Adolf Hitler claimed to be a socialist. The real socialist. His party was named: NSDP. The Nationalist Socialist Party of Deutschland.

The Nazis believed that Hitler would bring true socialism to Moscow.
The Nazi leader was presented as the true “peace maker”.
If the Germans followed his leadership, Herr Hitler would bring peace to the whole World.
Obviously also to Cuba.
Socialism is against capitalism.
If you see the Nazi propaganda material from 1937, you will see that the Germans saw the Yankees in North America as an enemy that has to be defeated.
Fidel Castro knew this. In the Communist regime’s need of help, any enemy of the USA would do. Also the good old Nazis.
Written by Ivar
Of course he knew, he’s just biding his time, until he gets what he thinks he wants from his communist cronies. But, his end is coming too.