He was taken to hospital with serious injuries and underwent surgery.
A source said he was recovering and awake. He had little memory of the crash and his mother had to tell him that Ethan was dead.
It is understood funeral plans are underway. Ethan's family were being supported by Victim Support, relatives and friends.
A third youth, also aged 16, was also hospitalised after the crash.
A police investigation into the crash is ongoing. The Waitemata Serious Crash Unit are making inquiries as to whether alcohol or speed were factors in the crash, where the boys were going and why they were in a stolen vehicle.
It is expected to be at least several weeks before the exact circumstances of the crash are established.
Ethan was a student at Rutherford College and previously attended Te Atatu Intermediate.
His friends paid tribute to him on his Facebook page yesterday.
"Rest easy brother, gona miss seeing you ... gone way to soon gone but never forgotten see you on the other side (sic)," one friend wrote.
A relative posted: "we are in pain and are grateful for all the love and support and concern".
Funeral details were yet to be announced, but it is understood Ethan's family were working together to plan a tangi for the teenager.