Because, according to his nephew, staff at the Dallas hospital where he was treated "didn't even give him a chance."
"Nobody tried to help Eric," Josephus Weeks said Friday night. "... If they would have given him a chance, he would have fought his way through."
In an emotional interview with CNN's Erin Burnett, Weeks alleged that Texas Health Presbyterian Hospital officials "said no to everything" relatives requested and "lied to us the whole time." He also accused the hospital of giving Duncan inferior treatment because he was poor, had no health insurance and was black.
"Had (he) been another color, he probably would be living today, he would have survived it," he said. "And that's what's really hurting me the most: ... They treated him the way they did because of the color of (his) skin.
"... You stand a chance if you're white, but not if you're black."
This wasn't the first time members of Duncan's camp have made such claims.
Responding to these allegations, the hospital issued a statement Thursday defending its handling of the 42-year-old Liberian national's case.
Its involvement started September 25, when Duncan first came into its emergency room with a fever and was let go four hours later; resumed September 28, when an ambulance brought him back; and ended with his death Wednesday morning.
During that first visit and again after his admission -- when more than 50 people cared for Duncan in a 24-bed intensive care unit set aside for his care -- the hospital said, "Our care team provided Mr. Duncan with the same high level of attention and are that would be given any patient, regardless of nationality or ability to pay for care."
The hospital said: "We have a long history of treating a multicultural community in this area."
In its Thursday statement, Texas Health Presbyterian addressed other criticisms as well.
Why wasn't he immediately given an experimental drug? Because one wasn't available, the hospital explained.
Why didn't he get a blood transfusion, like other Ebola patients in the United States? Because "his blood type was not compatible with the serum donors."
As to Duncan's condition the first time he went to Texas Health Presbyterian, the hospital said he had a "low grade fever and abdominal pain," and was released with some antibiotics and a pain reliever.
Weeks claims that discharge papers show that Duncan, in fact, had a 103-degree fever when he left the hospital.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNN on Thursday -- as he and other officials have said previously -- that "clearly there was a misstep early on when he wasn't diagnosed immediately" in that first ER visit. There have been criticisms that hospital staff didn't process the fact Duncan had come from Liberia, where Ebola has infected and killed thousands.
But Fauci said that blaming the hospital for Duncan's death is "misplaced," even if it is "understandable" for a mourning family.
"I just can't believe that he was deliberately treated in a less well way than others," said Fauci.
It seems no explanation, no justification, will wipe away Weeks' grief for a man he called "my brother, my uncle, my best friend" as a "very good person' who would help anyone regardless of their skin color, their health condition or anything else.
Wiping away tears, Weeks said that, while he's obviously upset at the Dallas hospital, he would be fine if Duncan could miraculously come back to life.
"(But) he's dead. There's nothing you can do," the nephew said. "You can't bring him back ... I can't have him (back). I never will."