I didn't know that, actually. I looked it up and found that while food and humanitarian aid aren't blocked, they are required to be paid with cash and not credit. I can't find any information about fuel being allowed. I could totally be wrong, but I couldn't find any source to back it up.
Most fuel in the Caribbean is bought from Mexico in any case. I know that the USVI is that way, and I suspect Puerto Rico does too. The cost of transport is less. Mexico has a delivery route for fuel through the islands. But, yes, there are barges sailing from the Port of Miami twice a week with a stop in Cuba. It can carry fuel.
I just find it interesting how some love to blame the US first for issues in other countries.
I just find it interesting how some love to blame the US first for issues in other countries.
It is a known pattern. Even the article itself points out the U.S. has a hand in the current crisis:
The nation of 11 million is experiencing its worst economic crisis since the collapse of the Soviet bloc in the 1990s due to fallout from the coronavirus pandemic, the recent tightening of US sanctions and structural weaknesses in the economy.
I took that last line to mean the monetary sanctions the US placed on Cuba. No money can be transfered from the US and no credit lines can be had from US banks.