The devoted Sunderland supporter suffered from a rare form of cancer neuroblastoma and had of late been receiving palliative care at his home.
Defoe, who had touchingly been accompanied by Lowery onto the Wembley pitch when the striker made his England return after a four year hiatus against Lithuania in March, broke down in tears on Thursday when asked about him declaring his ‘best mate’ only had days to live.
Confirmation of the 34-year-old’s fears arrived on Friday.
“My brave boy has went with the angels today 07/07/17 at 13:35, in mammy and daddies arms surrounded by his family (with several heart icons),” read a message from the family on Bradley’s Facebook page.
“He was our little superhero and put the biggest fight up but he was needed else where.
“There are no words to describe how heart broken we are.
“Thank you everyone for all your support and kind words.
“Sleep tight baby boy and fly high with them angels.”
Sunderland — who had donated towards a possible treatment for him in the United States which sadly was called off — issued a long statement.
“Bradley captured the hearts and minds of everyone at our club with his indomitable spirit, tremendous courage and beautiful smile, which could light up even the darkest of rooms,” read the statement.
“Despite battling neuroblastoma for much of his all too short life, he demonstrated a bravery and fortitude beyond his years that humbled us all. He was truly an inspiration.”
Sunderland, whose miserable season which saw them relegated from the Premier League was given a brighter hue by Lowery’s presence, asked for the family to be allowed to grieve in peace and referred to Defoe — who has moved to Bournemouth — and their heart-warming relationship.
“He had a special relationship with Jermain Defoe and their feelings for each other were evident for all to see. Jermain, naturally, is heartbroken,” the club said.
Sunderland will commemorate his passing almost immediately as they are playing a pre-season friendly with Bury later on Friday with the latter club saying they will hold a minute’s applause for him.
Lowery and his courageous battle was exposed to a wider audience at the beginning of last season as at the Premier League game between Everton and Sunderland his name was chanted by both sets of fans in the fifth minute — as he was then five — and Everton then donated generously to the fund for his proposed treatment in the United States.
The funds raised will now be placed in a foundation in his name, according to Sunderland.
Despite his failing health his spirit and resilience were remarkable and he went on to jointly win the BBC Premier League goal of the month competition in December — converting a penalty past Chelsea reserve goalkeeper Asmir Begovic at half-time of their game.
He subsequently received 250,000 Christmas cards.
Defoe was a regular visitor to his home and he and Lowery were given the honour of being listed on the race card for the world’s most famous steeplechase, the Grand National, in April this year.
The race organisers allocated them number 41 on the card — 40 are legally allowed to race — with the youngster listed as the jockey and Defoe as the trainer and naturally the silks (colours) were the red and white stripes of Sunderland.
Sadly things by that stage had deteriorated further with a new tumour detected at the base of his spine.
By the time his sixth birthday had come round last month Lowery was back in hospital but Defoe celebrated it with him once he was discharged.