No, I think they’d love to replace him but he’s an insane egotist who can’t imagine quitting, even if he tanks his whole legacy and the Democrats with it.
In Cuba, no political party, including the Communist party, nominates or campaigns for candidates for office- all candidates run as independents. Political parties under socialist systems play a different role than under Liberal capitalist systems. Parties under capitalism represent the competing interests of factions of the Bourgeois ruling class, while parties under socialism ideally (not always in practice, unfortunately) represent the interests of the whole of the working people and society. Socialist states also typically take the position that the process of democracy doesn’t stop with elections and voting, but is a continual process whereby the people are consistently engaged and participating in their government. That is why this post emphasizes the role of various mass organizations in Cuban democracy- these are the democratic institutions of the country, not just political parties. You can contrast that to a bourgeois system, whereby two or more bourgeois parties run mass advertising campaigns, rendering the vote as essentially a consumer choice analogous to picking political representatives like choosing between Coke and Pepsi, while the people have little actual say in some of the most important parts of their lives.