“My brave boy has went with the angels today… in mammy and daddies arms surrounded by his family,” a Facebook post said.
“He was our little superhero and put the biggest fight up but he was needed elsewhere.
“There are no words to describe how heartbroken we are. Thank you everyone for all your support and kind words.
“Sleep tight baby boy and fly high with them angels.”
Sunderland Football Club, for whom Bradley had been a mascot, praised the six-year-old’s “indomitable spirit, tremendous courage and beautiful smile, which could light up even the darkest of rooms.”
On Thursday, England forward Jermain Defoe who had formed a close bond with the youngster, broke down during a news conference at his new club Bournemouth when asked about Bradley’s health.
The superstar striker, said: “There is not a day that goes past where I do not wake up in the morning and check my phone or think about little Bradley because his love is genuine and I can see it in his eyes. It is special.”
The six-year-old had been battling a rare form of childhood cancer – neuroblastoma – since he was just 18-months old.
However, after beating the disease once, it had returned again in July 2016. His condition has deteriorated quickly over the last few weeks.
It was when appearing as a mascot for Sunderland’s Premier League match against Chelsea in December 2016, that Bradley had struck up a friendship with his “best friend” Defoe.
The football star had often visited him in hospital, and last week attended a party Bradley’s family had held for him.
A minute’s applause will be held for Bradley ahead of Friday’s match between Sunderland and Bury Football club, with the players and fans paying their respects to the mascot and his family.