Sanctions don’t usually work on regimes like this. It’s pretty obvious it won’t work on Cuba. Why not ease the burden on its people? Some prosperity might help. Might not. Certainly our current policy is worthless. Failing invading Cuba and hanging the Castros and their apparatchiks I don’t see any point in continuing a failed policy.
So you’d rather that we trade freely with them so that they can be rich communist dictators like China instead of poor ones? Heck, if we try hard enough we might be able to help them build up a nice, strong military like China.