In GF2, when Michael's black-hatted bodyguard was about to kill a comatose Roth in his hospital bed, the Cuban military (or a police unit) was there to stop him. How did they know Roth was in danger? Who tipped them off?

Did Fredo have anything to do this (remember Michael told him earlier that Roth would not see the new year). And why would they even bother to get involved? I realize that Roth had friends in high places in the Cuban governement, and that they would want to protect Roth, but with the government toppling and the president stepping down that same night, you would think they had more important things to worry about than protecting a crony like Roth.