No. We need the facts on the educational level of the Cuban people before Castro and after. We also need to compare that level to that of the other nations in the Caribbean.
If educational level improves in the wake of post-capitalist changes, it is because the poor are deprived of easy money as a better alternative to education.
Teachers in rich countries also try to convince poor kids to stay in school and study hard, but many think they can just get rich in pro-sports, the music industry, or in other ways that don't require education. These are all mostly either pipe dreams that only a very small percentage of people will actually achieve, or they're illegal industries that will eventually land kids in jail or worse, but it creates a culture of education not being worth enough to put effort into.
In poor/communist countries, there's no (fake) dream of easy money and getting rich quick, so education is people's best hope. This is true whether 'communism' had been adopted, as in Cuba, or whether there's just widespread poverty and missionaries come in and offer people education along with other basic services that are better than nothing.
In countries that are rich/well-off, there's always an easy-money-dream deterrent from education. Even educational institutions in such countries/economies cater to the will to only focus on what is needed to get jobs and make money. Once upon a time, Europe and its diaspora was motivated by poverty and war to cultivate a higher culture through liberal arts education, in hopes that wisdom would avert social problems and more war. What has happened, however, is that economic growth has brought with it more and more specialization and arrogance vis-a-vis liberal arts, philosophy, etc. so now people are morally/ethically poor despite material wealth, which doesn't satisfy them because they quantify their wealth relative to others who have more instead of focusing on the immense wealth that even the lowest middle-class people have in developed countries/economies.
So now the moral/ethical gap has evolved into social-justice inequality thinking that only stokes envy and social division, and people are dismissing traditional morality and ethics as some kind of bourgeoisie-trick-over-the-proletariat wash. The global middle-class needs a reality check and a back-to-basics step-back from industrial-consumerist materialism that drives global markets, not socialism/communism that seeks to further enrich the middle-class by increasing taxes and spending to invigorate even more economic growth.