Calls that Abdel Baset al-Megrahi be returned to prison have increased in the U.S. and Europe since rebel forces seized Tripoli last week.
"He is between life and death, so what difference would prison make?" said his brother, Abdel-Nasser al-Megrahi, standing outside the family's house in an upscale Tripoli neighborhood.
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Abdel Baset al-Megrahi, who was convicted for the bombing in 2001, was freed from a Scottish jail on compassionate grounds in August 2009, after doctors estimated he had three months to live. He was greeted as a hero in Libya and appeared on TV in a wheelchair at a pro-Qaddafi rally.
His release, after serving eight years of a life sentence, infuriated the families of many Lockerbie victims, most of whom were American. Some critics of his release have long suspected it was motivated by Britain's attempts to improve relations with oil-rich Libya.
Two New York senators recently asked Libya's transitional government to hold al-Megrahi fully accountable for the Pan Am bombing. Under the terms of his release, the bomber was ordered to live at his home and provide a monthly medical report.
On Monday, Scottish officials overseeing his parole said they had been in contact with his family, with the government saying in a statement that his "medical condition is consistent with someone suffering from terminal prostate cancer."
On Monday, rebel Justice Minister Mohammed al-Alagi said there was no legal case for al-Megrahi to be charged or deported to the West. But he also said the rebel government would discuss all such issue with concerned governments once a democratic assembly was in place.
Abdel-Nasser al-Megrahi, though, said his brother can barely communicate.
"He's in a coma," he said, adding that he occasionally awakes for a few minutes and asks for his mother. "He doesn't move, not even in his bed."
He said his brother's health required him to stay at home.
"It is natural for him to be with his family and his mother," he said. "Anyone, either Libyan or Scottish, would have mercy."
Little was known about al-Megrahi. At his trial, he was described as the "airport security" chief for Libyan intelligence, and witnesses reported him negotiating deals to buy equipment for Libya's secret service and military.
But he became a central figure -- some would say pawn -- in both Libya's falling out with the West and then its re-emergence from the cold.
To Libyans, he was a folk hero, an innocent scapegoat used by the West to turn their country into a pariah -- whose handover to Scotland in 1999 was seen as a necessary sacrifice to restore Libya's relations with the world.
In the months ahead of his release, Tripoli put enormous pressure on Britain, warning that if the ailing al-Megrahi died in a Scottish prison, all British commercial activity in Libya would be cut off and a wave of demonstrations would erupt outside British embassies, according to leaked U.S. diplomatic memos. The Libyans even implied "that the welfare of U.K. diplomats and citizens in Libya would be at risk," the memos say.
But in the eyes of many Americans and Europeans, he was the foot-soldier carrying out orders from Libyan leader Moammar Qaddafi's regime. Tony Blair, Britain's prime minister at the time of the conviction, said the verdict "confirms our long-standing suspicion that Libya instigated the Lockerbie bombing."
The bombing that blew up Pan Am Flight 103 on Dec. 21, 1988, over Lockerbie, Scotland was one of the deadliest terror attacks in modern history. The flight was heading to New York from London's Heathrow airport and many of the victims were American college students flying home to for Christmas.