A coroner has ruled that the Home Office’s “hostile environment” did not contribute to the death of a Windrush citizen who lost his life after spending months struggling to prove his right to live in the UK.

Dexter Bristol, 58, died in March 2018 after collapsing in the street. Heart problems were found to be the medical cause of his death.

The coroner, Mary Hassell, considered at a hearing at St Pancras coroner’s court on Monday whether the problems Bristol had had with the Home Office in the final year of his life trying to prove his right to live in the UK contributed to his death.

His mother, Sentina D’Artagnan Bristol, said in that year he was under enormous stress from the Home Office caused by having to try to prove he was British.

Bristol’s case emerged as part of the Guardian’s coverage of the Windrush scandal, which highlighted the damaging impact of the Home Office’s hostile environment policy on many individuals.

Bristol, who moved from Grenada to the UK in 1968 when he was eight, was sacked from his cleaning job in 2017 because he had no passport. He was denied benefits because officials did not believe he was in the country legally. Until he was sacked, he had no idea there was any problem with his immigration status. He feared being deported after he was told he had no right to live and work in the UK.

Two medical experts differed on the role the stress he was under may have played in his death.

Prof Jaswinder Singh Gill, a consultant cardiologist, told the inquest “I’m pretty sure stress was a factor” contributing to Bristol’s death. However, the pathologist Dr Alan Bates, told the court he did not believe that stress was a causative factor in the death.

Mark Pembroke, from the employment agency Maximus, said in a statement read out in court that Bristol had problems with obtaining the evidence the Home Office required to prove he had a right to live in the UK.

“Nothing appeared to be moving quickly enough to allow him to gain employment,” he said. “He felt he was going round in circles. It made him feel like a criminal but he hadn’t done anything wrong. I could see Dexter was unravelling. It was a slow, gradual decline.”

His immigration lawyer, Jacqueline McKenzie, of McKenzie, Beute and Pope, had worked with him in the 10 months before his death to help him try to regularise his status. She told the court she saw him decline in the months before his death.

“He kept saying ‘I’m British’,” she said. “Dexter said that in May 2017 he had spoken to the Home Office and they had said to him that he was not British and had no right to be in the UK.”

She said his biggest anxiety was that he might lose his benefits including housing benefit, which would result in him losing his home. “He was always very sad,” she told the court. “He just didn’t believe this was going to be resolved.”

Najmin Syed, a senior policy adviser in the Home Office’s nationality and settlement casework team, said the Windrush scandal had led to the Home Office adopting a more “commonsense” approach in cases like Bristol’s.

When the coroner asked her what had changed in terms of the requirements for Windrush generation people applying to regularise their status she said that the key requirements of proving identity and residence in the UK since 1 January 1973 remained but the Home Office was adopting a “more customer proactive approach”.

The coroner said Bristol had died of natural causes although he was suffering from various stresses before his death. She did not find that the Home Office’s hostile environment was a contributory factor in his death.

Speaking after the inquest his mother condemned the coroner’s conclusions.

“Justice has not been done,” she said. “Dexter was going through a lot of stress because of the Home Office and I believe it was those stresses that brought on his collapse and death.”