Cuba probably has the best health system in the world when compared to per capita GDP, that canīt really be disputed (though the why of this might be argued over to an extent). Which isnīt to say I approve of other things about Cuba.
One should always be skeptical about dictatorships and their statistics though. In Sweden there is a famous quote from our then prime minister in the 80s along the lines of "say what you want about the Soviet Union, but if there is one thing they know it's how to create economic growth"
I don't know much about Cuba and their health care but I retain suspicion about those kind of countries.
One should be suspicious of all statistics, fool.
Especially the stats that don't fit ones preconceived notions.