For a long time.
The brothers have already lost their father to political assassination - in 1999 in Quetta, Pakistan - when he was trying to warn the world that the Taliban were a danger that could spread beyond Afghanistan.
Now Hamid Karzai is making enemies by trying to rid his country of warlords as part of his strategy for promoting peace. The warlords, though, a disparate group of mobster-like thieves, possess the dangerous combination of greed and ruthlessness, and their fiefdoms are at stake.
"Yes," Qayum Karzai says finally, "I think he's in some danger. I think there's a danger that's inherent to what he's doing, in a country where stability has not taken over yet. Disarmament hasn't occurred, which means security is not what it should be. And there will be no security until the warlords are gone."
Qayum Karzai has become one of his younger brother's closest advisers. He was in Afghanistan in June helping at the loya jirga, the political council that gave Hamid Karzai 18 months as president of the interim government.
It was Qayum Karzai who recommended that Ashraf Ghani, a Johns Hopkins University adjunct professor and former World Bank official, become the new government's finance minister, among its most important positions.
And while the Afghan president works to bring various factions together and encourage rebuilding in the country, Qayum Karzai has been working the halls of the U.S. Congress and traveling to his native country to help where he can - which means in small villages and in the presidential palace, where he has made a habit of imparting his advice to his brother.
"We have some very frank discussions," Qayum Karzai says, sitting in a Kabul guest house recently before traveling to southern Afghanistan to break ground for a vocational center. "He's open to advice, but he also has ideas of his own."
Typical of the relationship between the brothers, Qayum Karzai arrived with news that a public relations effort was needed in Washington. News outlets had been reporting - based on interviews with disgruntled commanders loyal to the Taliban, he insists - that tensions in Afghanistan were running high between ethnic Pashtuns and Tajiks.
"You would think an ethnic war is going to break out at any minute," he says. "The reporting was giving the impression that the country is on the verge of collapse. That's nowhere near the case."
Public relations is not a small consideration - either inside Afghanistan, where Hamid Karzai's government is preaching patience with promises that happy days are ahead, or outside the country, where money must be tapped to make the promises come true.
"I told him there is a barrage of propaganda out there, and it's coming from people who want to see this government fail," Qayum Karzai recalls. "He was very calm. He said, 'I cannot foresee a scenario where this won't happen. This is part of the journey. We worry about it only to the extent that it gets in the way of our objective - to stabilize Afghanistan.'"
The Karzai brothers were raised in Kandahar. Their father, Abdul Ahad Karzai, served as deputy speaker in the Afghan government in the early 1970s. Qayum Karzai came to the United States about the same time to learn how to fly jets for the Afghan air force. Motion sickness grounded him after eight months.
He enrolled in Montgomery College in Germantown and studied biology, political science and economics, then earned a degree in political science from American University. He was attending graduate school at American when the Soviet Union invaded Afghanistan in 1979. He dropped out before getting his doctorate. Looking back, he thinks he might have been suffering from depression.
"Human psychology is amazing," he says. "I thought the invasion was the work of educated people, so I left school."
He took a job with Marriott Corp., busing and then waiting on tables. He worked his way up to manager of a Bethesda restaurant. In 1985, he opened the Helmand Restaurant in Chicago, a precursor to the restaurant of the same name on Charles Street in Baltimore, which opened in 1989.
He opened a third restaurant, also on Charles, and hopes to add one in Bolton Hill. He and his wife live in Glenwood.
By 1989, his family had fled to Pakistan, and his father and particularly his brother joined the resistance to the Soviets.
Civil war took over when the Soviets were chased out of Afghanistan. When the Taliban filled the power vacuum, Qayum Karzai lobbied in Washington while his brother and father were in Pakistan.
His father's assassins, he believes, were with the Taliban.
Qayum Karzai is the first to admit he was not sure his brother could handle the job of bringing together such a torn country. He is also the first to admit he was wrong about that.
Hamid Karzai, a Pashtun, has moved to include Tajiks in the country's ministries. He has put the warlords on notice that different days are ahead - but has been moving slowly to buy time, and hopefully support, for his government without the warlords causing too much trouble.
His moderate style and his appointment of Western-educated technocrats helped attract a pledge of $1.8 billion for Afghanistan from the rest of the world earlier this year. And although the money has been slow to arrive, the donations have helped enough to make his government relatively stable.
Now, besides advising the president, Qayum Karzai is setting up a vocational school in Afghanistan near Tarin Kot and is trying to forge ties between that city and Baltimore.
The country is large and there are a lot of people with needs, he says, but the project is a start.
He tells a story to underline the urgency. Walking in Kabul early in the morning, he passed a boy of about 8 sitting on the sidewalk, behind tiny pyramids of almonds that he was selling. Karzai saw him again that evening and tried to talk to him.
"If you're not buying, go away," the boy said.
"He was so bitter," Karzai recalls. "I knew he must be an orphan, a victim of war. And I thought if a young kid has this kind of bitterness because of things that have happened to him that he couldn't control, where will he end up when he's 16? He's a future drug dealer, a terrorist or a gunman. That told me something has to be done."