LOL! I’d pick Bolivia because the Andean region is a great place to hide. You can buy “air cover” real cheap, and the borders are porous. Things too hot in La Paz? Just slip on down to Buenos Aires. Tell ‘em Klaus Barbie sent you.
There is nowhere to hide in South America if the CIA is after you. Russia, or China, or Muslim countries would be better. Venezuela is US's backyard. He would have to be on guard 24/7/365, but the extraction force would only need to get one favorable occasion. As an extreme measure, they will just send a word that his head would be well paid for. I do not see how he can survive, short of a major surgery and fake ID.
LOL Klaus Barbie is pretty close to moi backwards. But no cigar.