Singer Will Young has questioned why his twin brother was not assessed by a consultant psychiatrist when he was admitted to hospital after trying to take his own life, just days before his death.
Rupert Young, 41, died after jumping from a bridge in London on July 30 last year, an inquest heard.
His death came just days after he was admitted to St Guy's and St Thomas's Hospital on July 28, when he had been seen walking along the edge of a bridge in the capital.
St Pancras Coroner's Court in north London was told he had been admitted to hospital four times in the week prior to his death, as he struggled with alcoholism.
He was trying to avoid homelessness and told hospital staff he had been attempting to contact his father for a place to stay, before discharging himself, the inquest heard.
Senior coroner Mary Hassell gave a ruling of suicide at a hearing on Monday, finding that Rupert had intended to take his own life.
Following the conclusion of the inquest, Pop Idol winner Will Young said it had been a difficult time for himself and his family.
"Those working within the NHS do an amazing job under very difficult circumstances," he told reporters.
"And it's never been more hard-pressed than at the moment, of course.
"However, my brother is someone who had, in the months and weeks before his death, been into hospital on countless times following suicide attempts."
Young said he was "astounded" that his brother had been allowed to leave hospital two days after his suicide attempt without being referred to a consultant psychiatrist.
"It is my belief that it must, or should have, been obvious to all concerned that he was at high risk of suicide and should have been detained under the Mental Health Act for his own safety," he said.
"Had this been done, he might still be alive today.
"I know we are not the only family in this situation and I pray that lessons are learned from this situation and that some of these deaths are prevented in the future."