HAVANA — Fidel Castro is on the mend, gaining weight, exercising twice a day, and helping to make the Cuban government’s top decisions, his brother Raul Castro says.

The island’s acting president gave the first clues about his brother’s health in weeks, saying during a Monday speech that he has a “healthier mentality, full use of his mental faculties with some small physical limitations.”

At 76, Raul is five years younger than his ailing brother, who has not been seen in public since announcing he had undergone emergency intestinal surgery and was stepping down in favor of a provisional government in July 2006.

But the younger Mr. Castro said his brother remains a key voice in government and that Communist Party leaders support his re-election to Cuba’s Parliament, the National Assembly — a move that could allow Fidel Castro to keep his post as president of the Council of State.

“We consult him on principal matters, that is why we the leaders of the party defend his right to run again as deputy of the National Assembly as a first step,” Raul Castro said.

Though Fidel Castro’s condition and even his exact illness are state secrets, he has officially retained his post atop Cuba’s supreme governing body, the Council of State. Parliamentary elections take place January 20.

Last week, the older Mr. Castro suggested he would not cling to power forever, nor stand in the way of a younger generations of leaders. It was the first time he hinted at his political future since falling ill, though Raul’s comments Monday could indicate his brother has no intention of retiring permanently.

Through daily exercise, Fidel “has recovered a lot of weight and muscle mass,” he said, speaking to voters in Fidel’s voting district in Santiago, an eastern city where the brothers spent part of their youth. He said Fidel asked him to visit voters and trump up support for him because he was unable to personally.

In afternoon remarks that were carried nationwide on Cuban state television Monday evening, Raul said his brother “has more time, he’s reading more than ever. He’s meditating more than ever and writing almost more than ever.”

Speaking of Cuba’s electoral system, Raul Castro noted that American democracy pits two identical parties against one another, and joked that a choice between a Republican and Democrat is like choosing between himself and his brother Fidel.

“We could say in Cuba we have two parties: one led by Fidel and one led by Raul, what would be the difference?” he asked. “That’s the same thing that happens in the United States … both are the same. Fidel is a little taller than me, he has a beard and I don’t.”

Raul scoffed at the notion Cuba needs to be more like America. But he also acknowledged that the island’s communist government has its flaws, saying, “Our system has to become more democratized.”

But he did not elaborate on what a more democratic Cuba might look like.

“I want to say this: If we only have one party that represents the interests of the people, where we can have differences, we should have them,” he said. “Not class clashes, but it’s good to have differences.”