A 23-month-old boy with a rare degenerative brain disease who was at the centre of a protracted legal battle has died, his parents have said.

Alfie Evans died at Alder Hey children’s hospital in Liverpool in the early hours of Saturday morning.

Announcing the news on Facebook on Saturday, his parents, Kate James and Thomas Evans, said: “Our baby boy grew his wings tonight at 2:30am. We are heart broken. Thank you everyone for all your support.”

Life support was withdrawn on Monday after a last-ditch appeal to the high court was turned down.

Alfie had been in a semi-vegetative state and scans of his brain had shown that almost all of it had been destroyed. Judges had agreed with doctors that further treatment would be futile and there was no hope of him getting better.

His parents, who are both in their early 20s and from Liverpool, had insisted their son was not in pain or suffering, but lost cases in the high court, court of appeal, supreme court and European court of human rights.

Pope Francis, who met Alfie’s father, tweeted:

I am deeply moved by the death of little Alfie. Today I pray especially for his parents, as God the Father receives him in his tender embrace. — Pope Francis (@Pontifex) April 28, 2018

More than 1,000 people gathered to release balloons in Springfield Park, next to the hospital.

Evans and James did not attend. Evans’s sister Sarah told the crowd: “I just want to thank you all for coming today. Our gorgeous little warrior took his last breath at 2.30 this morning.

“Our hearts are broken. We are absolutely shattered as a family. Thomas just wants to thank you all for the support you’ve all shown. There’s only one Alfie Evans.”

People release balloons outside Alder Hey children’s hospital. Photograph: Peter Byrne/PA

Evans said on Thursday that their lives had been “turned upside down by the intense focus his son’s case had received in Britain and around the world.

“Our little family along with Alder Hey has become the centre of attention for many people around the world and it has meant we have not been able to live our lives as we would like,” he said.

The attention and emotion that Alfie’s plight attracted and his parents’ determined public campaign to get the treatment they believed he needed led to high tensions between supporters and staff at Alder Hey.

Hospital managers said they were shocked at the barrage of abuse that came from some quarters when they found themselves “at the centre of a social media storm”. It led Merseyside police to issue a warning over comments being made about the hospital online.

After accepting that their options had been exhausted, Alfie’s parents sought to build bridges with medical staff and pledged to work alongside doctors to give him the dignity and comfort he needed.

In a statement issued on its website, Alder Hey children’s hospital said: “We wish to express our heartfelt sympathy and condolences to Alfie’s family at this extremely distressing time.

“All of us feel deeply for Alfie, Kate, Tom and his whole family and our thoughts are with them. This has been a devastating journey for them and we would ask that their privacy and the privacy of staff at Alder Hey is respected.”

The archbishop of Liverpool, Malcolm McMahon, said on behalf of the Catholic Bishops’ Conference of England and Wales: “I would like to express my deepest sympathy at this moment of loss to Tom and Kate as we hold little Alfie in our prayers. All who have been touched by the story of this little boy’s heroic struggle for life will feel this loss deeply. But as a Christian Alfie has the promises of God, who is love, to welcome him into his heavenly home.

“Although the past few weeks have been difficult with much activity on social media, we must recognise that all who have played a part in Alfie’s life have wanted to act for his good, as they see it.

“Above all, we must thank Tom and Kate for their unstinting love of their son, and the staff at Alder Hey hospital for their professional care of Alfie. Now it is time for us to give Tom and Kate space to grieve their son’s death and offer our prayers for him and consolation for all.”