Via Punt de Vista (my translation):

Daughter of Fidel says that with Diaz-Canel, Castro buys time to prepare a successor from the family

Fidel Castro's daughter, Alina Fernandez, told NTN 24 that the naming of Miguel Diaz-Canel as the number two leader behind Raul Castro is nothing more than an attempt by the regime to "buy some time." According to Fernandez, the objective is to have more time to create "a leader from the family." For the daughter of Fidel, who lives in the United States, the Castro brothers are "the kings of improvisation," and she says that "the only reason this dictatorship continues to exist is because it receives all types of support from the outside."

See video of her statements HERE.