HAVANA — Hilda Molina was once a celebrated member of the Cuban elite. The neurosurgery unit that she created received regular visits from Fidel Castro, who was proud that his health service was capable of such advanced medicine.

Now Dr. Molina sits in her home in Havana hoping that one day she will be reunited with her son, Roberto. She is an outcast now, a dissident enduring the constant attentions of the Cuban security service.

But that does not stop her from speaking her mind, and not in the whisper preferred by most Cubans when speaking of Mr. Castro and the succession. She searches in an English-Spanish dictionary for the right word. “Treason,” she says. “Fidel committed treason to the revolution. He promised liberty and equality 47 years ago. And look now. This is a sick society.”

The dream for Dr. Molina died when the unit she founded, the country’s first, was told to give priority to paying patients from abroad. Before long, it became a facility available only to the elite. The poor disappeared.

Dr. Molina spoke out and paid the inevitable price. Now 63, she is unable to visit Roberto, who fled to Argentina.

“In the beginning, I respected Fidel. But now his government speaks one thing and does another.”

Cuba’s dissidents have new cause for hope, following Mr. Castro’s surrender of power after an emergency gastro-intestinal operation on July 31.

But yesterday, their community received news of the death of Gustavo Arcos Bergnes, also a comrade of Mr. Castro in the early days of the revolution, but who was later imprisoned for criticizing the regime. He died of a heart attack here on Tuesday.

A day earlier, the regime said a “peaceful succession of power” had taken place after Mr. Castro’s operation.

Cubans are waiting to see if Mr. Castro will make any kind of appearance on his 80th birthday on Sunday. Some believe him already dead. His health has been declared a “state secret,” but it now seems that he is too ill to resume power, a seismic event in a country where three generations have known no other leader.

Mr. Castro’s brother, Raul Castro, who controls the army and security apparatus, now heads an allegedly collective regime.

The wisdom in diplomatic circles in Havana is that Raul Castro, 75, will retire in a few years to be replaced by a figure from the Cuban elite, who will be favorable to America and the rest of the outside world.

Some will not want to wait that long. Cuba’s leading dissident, Oswaldo Paya, has published a post-Castro transition plan that seeks to remove the Communist Party from power without undermining stability.

But his organization is weak — two-thirds of its membership have been arrested — and largely unknown to a population with very limited access to the Internet and no access to a free press.

One European diplomat observed that the regime’s best hope is in the apathy of a people who have never engaged in electoral politics.

“You hear a lot of talk about illegal satellite TV dishes and how the people are learning about the outside world, but most are too busy trying to get money and watching Brazilian soap operas to rise up.”

Despite a huge donation of oil from Venezuela and credits from China, the Cuban economy is still in a perilous state. Tourism provides the main source of hard currency, but most people struggle to live on about $15 a month. Far from creating a workers’ paradise, the Castro regime has produced a generation of young people who hustle their way through life.

Dr. Molina wants change, but her vision would see a return to the idealism that fired Mr. Castro in the 1950s. It most likely won’t happen, of course.

In the meantime, she remains outcast but not downcast. “I am free because I am a dissident,” she says. “I think freely.”