Yah, but Castro has to keep more troops at home to keep the locals from throwing him out. I live in Chile and have know
many people (at least 20 professionals) who have visited Cuba as tourists, as doctors, etc. and the consensus is that the Cuban people would turn on a dime if given half a chance. I've also met a number of Cubans who have been allowed out of the country and most of those, after a few drinks will admit the same thing.
Castro provides what help he can but be certain that Cuba is a big hollow shell held up by Castro's own hot air. Cuban Communism will not survive him, and spends an inordinate amount of effort in maintaining itself afloat. It has less left over than you might think.
Hmmm... Cuban Communism will not outlast Fidel, eh?