No, I do not have a confirmation on this, and certainly I do not have a contact on the island, but I assume the above on a simple thing: the cuban dictator did NOT sign the document read on cuban TV last night.
Above, the original Castro signature taken from www.cubanews.ain.cu via Google Images search and the signature written on the document read last night. If the bearded beast is not dead, then the shit he must have taken must be a record-setting one, at the point of not letting him sign a document. Make your own conclusions.
Now that I think of it, if he's drowning in shit, then he must have had a brain hemorrhage, not some intestinal problem.