(CNN) -- In his final moments, 8-year-old Tyler Doohan managed to rescue six people -- including two younger children -- from a burning mobile home in upstate New York, authorities said.
A last-ditch effort, however, to save his disabled grandfather cost the boy his life. His body was found next to his grandfather, whom Tyler considered a best friend.
"It makes me really proud, it really does, but I just want him back," Tyler's mother, Crystal Vrooman, told CNN affiliate WHAM.
Tyler, an East Rochester resident, was staying at the home of relatives in the nearby town of Penfield on Sunday night when he noticed a fire in the single-wide trailer, said Penfield Fire Chief Chris Ebmeyer.
As firefighters and sheriff's deputies responded to 4:45 a.m. emergency call, Tyler was able to wake six other people in the small trailer, including two more children, ages 4 and 6, the fire chief said.
Then Tyler went back into the blaze to help his grandfather, who was disabled and would have been unable to get out of the home on his own, Ebmeyer said.
"By that time, the fire had traveled to the back of the trailer," said Ebmeyer. "Unfortunately they both succumbed to heat and smoke."
The pair were found together on a bed in the back room. It appeared that the boy was trying to lift his grandfather from the bed when he was overcome by the smoke and fire, the fire chief said. Tyler and his grandfather were like best friends, Vrooman said.
An online fundraising campaign on YouCaring.com had raised more than $28,000 as of Wednesday for Tyler's funeral and his family.
Another relative was found dead in a front room, although his exact relation to Tyler was not clear.
Earlier, fire officials had released a mistaken version of the incident, where the grandfather's and uncle's locations were switched, due to incorrect information provided by a family member.
Tyler's mother said the boy broke away from his aunt outside the burning trailer and ran back inside to try to save his grandfather.
"All I could think about is how he couldn't breathe," Vrooman told WHAM.
She added: "I'm just so grateful that he went with people that he loved. He didn't go alone."
The cause of the blaze is still under investigation but believed to be accidental.
The conditions of the six survivors were not immediately available.
Ebmeyer said the trailer had no working smoke detector. He said that with so many people in one small mobile home, one alarm could have easily woken everyone in time to escape.
There was at least one space heater inside the trailer, the fire chief said.
Several pets -- including dogs, cats, a rabbit and hamsters -- also died in the fire, Ebmeyer said.
The Penfield Fire Company -- a volunteer unit -- intends to create a public service initiative to spread awareness and get smoke detectors out to the public, he said.
Meanwhile, Richard Stutzman Jr., interim superintendent of the East Rochester School District, where Tyler attended fourth grade, issued a statement:
"In bravely and selflessly giving his own life, he was able to save the lives of six others -- and he truly is a hero."
CNN's Jean Casarez contributed to this report.