How difficult would it be to locate live relative in Cuba. I know their birth names and the names of their parents.

I'm thinking it's next to impossible but I figure I'll ask before I forget about the idea of contacting them.

Getting in contact with them would be important since their grand father is my great grand father.

I do have an uncle in Cuba. If he is willing to do the leg work for me, what would he have to do? If he doesn't want to look for the relatives, what steps can I take to locate them my self?

Thanks!