QUEENS -- The family of a 14-year-old boy with autism who has been missing since walking out of school Friday still clings to hope that he'll be found.
"We only get a few hours of sleep every day, our mom can't stop crying, we can't eat," said Danny Oquendo, Avonte's older brother.
"It's very tough on our family, but we believe he is still alive."
The family said their lawyer has filed a notice of claim with Comptroller John Liu's office against the school that they say had been responsible for keeping Avonte safe. The notice is the first step toward filing a lawsuit.
"It's obvious that the school is liable," Oquendo said.
He said the security guard did not prevent Avonte from leaving the school, and nobody told the family he was missing until an hour-and-a-half after his disappearance.
Jack Ryan, a spokesman for Liu, said the office has not received the document yet but said it may take as long as 24 hours to process.
A number of people have reported seeing Avonte but most haven't sounded credible, Oquendo said.
"People said that they spoke to him, and that's something that Avonte cannot do," the teen's brother said.
Oquendo added the family believes someone may be holding Avonte.
"It's very cold outside, I don't think he is just walking around," he said.
Police have been canvassing neighborhoods including Long Island City and Greenpoint in the hunt for Avonte, distributing flyers with his picture and asking residents for help. Officers have also searched subway tunnels looking for him, the family said.
Police officers are also sifting through hours of surveillance tapes, Oquendo said, but haven't reported anything promising thus far.
Capt. Thomas Conforti, commanding officer of the 112th Precinct, which includes Rego Park, said finding Avonte is his "No. 1 effort."
"As every day goes by, it becomes more and more intense, and we have to try and do everything we can to locate Avonte," Conforti said Wednesday night.
The law firm Mayerson and Associates offered a $5,000 reward for the safe return of the teen.
The family's attorney did not return phone calls seeking comment.