Police say Oquendo was last seen wearing a gray-striped shirt, black jeans and black sneakers. He is 5 feet, 3 inches tall and weighs 125 pounds.
Missing posters are being handed out and the surrounding areas are under investigation, WABC reported.
"He doesn't know that, you know, 'I can get hurt in the street, someone can grab me and take me.' He doesn't know that," Fontaine said Monday. "He doesn't know fear."
Autism Speaks employees and volunteers will be joining the search effort Friday, Volpe wrote in an e-mail.
"We're all just praying for his safe return and we want to do everything we can to support the family. People in our community are rallying together and doing what we can to ensure that he comes home," Volpe said.
A vigil for Oquendo is expected to be held Friday night in a park across the street from his school.
Anyone with information about Oquendo is asked to contact the NYPD's Crime Stoppers Hotline at 800-577-TIPS. The public can also submit tips at Crime Stoppers website, nypdcrimestoppers.com or text to 274637(CRIMES), then enter TIP577.