Alfie Evans, the 23-month-old toddler at the center of a high court lawsuit, died almost a week after his livelihood was withdrawn.
The Merseyside boy, who had a degenerative brain disease, died at 02:30, said his father Tom Evans.
On Facebook he wrote: "My gladiator put down his shield and got wings … absolutely heartbroken."
Alfie's parents lost legal challenges to a Supreme Court verdict that removed ventilation from the hospital
The campaign garnered broad media attention and saw his parents clash with doctors for caring for the child.
Alfie, who was born in May 201
He has been in a semi-vegetative state for more than a year.
Mr. Evans and Alfie's mother, Kate James, wanted to take the toddler to a hospital in Italy for treatment, but this was rejected by doctors who described continued treatment as "not in Alfie's best interests."