Did the brothers not anticipate the pain they'd cause to Tsarni, who can't believe that the faces of his own nephews are being televised worldwide?
Did they not know that life as they knew it would end with the blasts that killed three people and maimed more than a 170 others?
"It's not possible he did this thing," Alvi Tsarni said Friday of the older suspect, Tamerlan, who was killed Thursday evening, about 24 hours before Dzhokhar was taken into police custody. Even with overwhelming evidence against the brothers, Tsarni clung to the hope that this was a mistake.
The brothers' father, Anzor Tsarnaev, was more adamant about his sons' innocence. He even accused the U.S. government of framing the young men "because they are practicing Muslims."
"They were set up, they were set up!" he wailed, adding that "all hell will break loose" if Dzhokhar wound up dead like Tamerlan.
I might be tempted to say crazy things like that, too, if my child appeared as convincingly guilty as the Tsarnaev brothers do. Lord only knows what I'd say and do to maintain the fiction that all was still well in the only family I'd ever known.
But I hope I would have the strength, instead, of the brothers' other uncle, Ruslan Tsarni.
In an emotional and wrenching interview Friday with CBS, he spoke about the Boston victims. And of his nephews, he said, "I just wish they never existed. . . . I am wordless . . . the people who did this do not deserve even to exist on this earth . . . " They are, he said, "barbarians."
When asked what he'd like to say to the people of Massachusetts and to all those who'd traveled to Boston for the annual run, he was unequivocal.
"I would say that since I have an association [with the brothers] through blood," that he wanted to offer "sympathy, condolences." He wanted to say "that I am with [the public]. And if some of them might send their curses on me, I am ready to accept it because I am associated with these bastards.
"What else can I say?" he asked, sounding agonized. "What else can [a] normal person say?"
His acceptance of the situation despite his awful personal connection to it reminds me of Sue Klebold's acceptance during the Columbine High School massacre in Littleton, Colo., in 1999. Klebold's son, Dylan, was one of the shooters.
"While every other mother in Littleton was praying that her child was safe, I had to pray that mine would die before he hurt anyone else," she recalls in author Andrew Solomon's book Far From the Tree: Parents, Children and the Search for Identity.
"I saw the end product of my life's work: I had created a monster," she told Solomon. "For the first time, I understood how Dylan appeared to others. When I saw his disdain for the world [in a video Dylan had recorded before the rampage], I almost hated my son. I wanted to destroy the video that preserved him in that twisted and fierce mistake."
If her words are the antithesis of denial, so are the actions of David Kaczynski, brother of Unabomber Ted Kaczynski.
In 1996, David notified the FBI that Ted was no doubt the elusive mail-bomb terrorist who had killed three and wounded 23 over two decades.
It felt like betrayal to turn on his older brother, David said. But he had a moral obligation to stop Ted from taking another life.
If you go into any courthouse on any day of the week in any city in the United States, you will hear family members defend their guilty loved ones, no matter how high the stack of irrefutable evidence.
Family love - hopeful, unconditional, forgiving - can blind the best of us to the worst in those we love. It's the best thing and the worst thing about the ties that bind us.
The hardest thing is to untie those binds, for the sake of those who don't deserve the pain our loved ones have wrought.
On Twitter: @RonniePhilly