The family of Timothy McComb, 38, are seeking answers at an inquest following his death at Cottingley Court in Beeston, Leeds, in 2016.
A jury at Wakefield Coroner's Court was told that he was found hanged at the supported living unit, four days after being taken to St James's University Hospital following an overdose of prescribed medication.
The inquest heard that Mr McComb had a history of contact with mental health services, including in 2014, when he was admitted to a psychiatric hospital in a drug-induced psychosis.
In 2016, he was found accommodation at Cottingley Court, where he was found dead on August 26 that year.
The inquest heard that doctor Hari U Pai, who saw Mr McComb in the days before his death, was shocked by what happened and ceased working as a GP.
He said: "It's really affected me."
When asked if he had concerns about Cottingley Court, Dr U Pai said he did. He told the hearing: "Yes. Because they were doing repeated self-harming."
Mr McComb's sister Katie Siobhan paid tribute to her brother at the first day of the week-long inquest.
She said: "Timothy was our Peter Pan. He was who we turned to if we needed help or if we needed support."
Miss Siobhan said that in the months before his death, there had been a "marked improvement" in Mr McComb's mental health and he was volunteering at St George's Crypt in Leeds.
But he became fearful about money and of losing his accommodation.
Miss Siobhan said: "He was fixated on it." She added: "I don't believe he meant to do what he did."
The inquest heard that Mr McComb would carry with him a doll he called Dennis. The jury was told that he believed Dennis was a real person, although at one point he told a nurse it was "just a stuffed doll".
Consultant psychiatrist Christopher Buller, who was involved in assessing Mr McComb after he was sectioned in 2014, also said he was surprised to learn of his death.
He said: "It is a bit of a shock, the outcome."
The inquest before coroner Jonathan Leach is expected to run until Friday.