Nathan Brown, 19, died at Newcastle's John Hunter Hospital on Friday morning after he was placed into a medically-induced coma following complications from the flu, Fairfax Media reports.
Mr Brown reportedly spent the past four weeks battling acute pneumonia, a staph infection, collapsed lungs, kidney failure and fluid on his heart after he originally was struck down with Influenza A.
Despite his serious condition, Mr Brown's family had not given up hope he would pull through his illness.
His uncle Robert Brown set up a Go Fund Me page to help his nephew with the medical expenses accompanying his recovery.
Since its creation on September 20, the page has raised more than $11,000.
"It was just devastating to see a fit and healthy young man like that go downhill as fast as he did, unfortunately, his organs started shutting down and his lungs collapsed," Robert told the Seven Network on Thursday.
The Hunter New England Local Health District did not want to comment at this stage, a spokeswoman told AAP on Friday.
So far 93,413 cases of the flu have been reported in NSW alone in 2017, compared to a total of 35,537 in 2016.
As of September 15, 288 influenza-associated deaths have been registered or reported to state public health units, a spokesman for NSW Health told AAP.
