"The thing that's most paramount ... is that this should never happen to anyone else," the man's uncle, John Lewis, said.
Brandon Harris, 25, died Jan. 23 as an outpatient, sleep-study participant at the Emory Clinic Sleep Disorders Center.
His medical history included diabetes but his doctor recommended Harris for the study and deemed him healthy enough to participate, Lewis said.
As part of the sleep study, a camera was present in the room to monitor Harris' sleep. Lewis, the only family member who has seen the video, said it appeared that his nephew was waving multiple times in distress, getting no response.
"We saw him sit up just a little bit enough to wave his hand in some type of, I'm saying distressed but there was no audio," he said.
Lewis said he watched Harris wave his hand six or seven different times. He said he believes the medical staff at the center waited too long to help his nephew.
"I just can't describe, you know, the pain to know what a wonderful young man he was, how tender and loving he was to just not get the care that he needed at that time," he said.
In a written statement released Monday, Emory Healthcare officials said, "At all times during the sleep study, Mr. Harris was monitored and the providers appropriately attended to him."
He died of sudden cardiac arrest, according to the statement from Emory Healthcare, which is the largest health care system in Georgia.
Emory declined to answer questions or comment further on the specific care for Harris or the allegations surrounding his death.
The man's mother has hired an attorney.
Lewis described in detail the images he said he saw on the video taken the day of his nephew's death. He said it was difficult to watch.
"I mean, since he was 4 days old, he was just my boy and then to actually see him die like that was just all I can do," he said. "But I sat through it because I knew my sister wouldn't be able to and she asked that I would and that was the least I could do ... to see what actually happened".
Lewis said, in the video, after waving several times with no response, Brandon was able to move around enough to get to the end of the bed, sit up and briefly disconnect himself from the apparatus to which he was attached.
"Once that happened, this woman comes to the door and she finally comes over to his bed and he tells her I guess that he's having some problems and needs to go to the restroom ..."
Lewis said the woman leaves while, he assumes, Harris went to the restroom. He said she returns and tries to get Harris to go back to the bed.
"Obviously, he tells her no, that he's more comfortable standing up," Lewis said.
Lewis said that at some point on the video footage, two other people come in the room. He said Harris appeared to be having breathing problems and the people in the room appeared to be consoling him.
"At one point, he leans to his right and sort of eases his knee down to the floor and he collapses. ... I believe at that point -- I can't say definitively -- but I believe at that point he was dead," Lewis said.
He said he saw in the video that the people in the room did not give him Harris CPR or check for any vital signs.