Tyler Doohan was awoken by a burning blanket after a fire tore through his grandfather's mobile home in Penfield, New York, early Monday morning.
The boy, his grandfather and uncle were killed. Six other relatives, including four adults and two children (ages 4 and 6), survived because of Tyler's actions, authorities said.
"He saved six people. They all would have died if he hadn't woken up," said Chris Ebmeyer, chief of the volunteer fire company in Penfield.
Tyler's mother, Crystal Vrooman, says the last time she hugged her son goodbye he had a smile on his face. He had talked his mom into spending the night with his grandfather because school was off for Martin Luther King Jr. Day.
"[His grandfather] was his best friend, and he tried to save him," said Vrooman.
She has pieced together the story of her son's final minutes with the help of family members who were there.
Tyler was awoken when the blanket covering his sleeping 4-year-old cousin caught fire. He then woke up six of his relatives, who were all able to escape outside.
He then ran back to the room where his 57-year-old grandfather, Lewis Beach, was sleeping. Beach used a wheelchair and crutches after having a leg amputated because of health problems.
His aunt tried to stop and followed, but did not enter Beach's room which was surrounded by smoke.
"My sister had his hand, and I guess he let go of her and tried to get my dad," said Vrooman. "She opened the window, and he wasn't there anymore."
Tyler's body was found in the rear of the home, a few feet from Beach's.
"They were lying in the bed together, trying to get to the window," said Vrooman. "I am so grateful he went with people that he loved, that he didn't cross over alone. And I am so glad that he was with his best friends."
The body of the boy's 54-year-old uncle, Steven Smith, was found in another part of the trailer.
The cause of the blaze appears to have been electrical in origin, but the investigation continues.
All six survivors of the fire suffered minor injuries, including Tyler's 65-year-old grandmother.
Vrooman says she will always remember her son as a hero.
"It makes me really proud, it really does, but I just want him back," she said.
CNN and The Associated Press contributed to this report..