Avonte Oquendo disappeared from his Queens school on Oct. 4, setting off a massive search that included extensive searches of subway tunnels and regular announcements over the public-address system at subway stations.
His remains were found in the East River in January, several miles from where he vanished.
Oquendo had a form of autism that made him nonverbal.
The family's lawyer has filed a notice of claim, the first step in suing the city.
