Alex Renton's family has posted on a Facebook page dedicated to his journey that he died surrounded by his family, listening to music and tummy full of his mum's food.
The family said they were very grateful for the support they've received.
Alex had been in an induced coma in Wellington hospital for two months after a seizure, and has been receiving cannabis oil brought in from the US as treatment.
His sister Jessie posted on Facebook tonight "Fly high my darling boy, I know you will be next to me every step of the way. I love you Alex and couldn't be prouder of everything you have achieved. You are free now my bro."
Alex was in a coma in Wellington Hospital after suffering a seizure in April this year and in June was prescribed cannabis oil. His mother Rose Renton said at the time it was hoped it would bring her son back to consciousness.
Mrs Renton said after the treatment he opened his eyes and moved for the first time in weeks.
"He's close to the surface but certainly not conscious and awake," she said.
The cannabis oil worked by "unlocking" the brain's neurons to allow epilepsy drugs to take effect.
"It oils the neurons in the brain, when you're in seizures and they're locked off the anti-epileptic drugs can't get underneath to release them to enable them to work and stop the seizing."
The news has caused an outpouring of sadness and support for the Renton family on social media.
