By Jo Hollis
Ms Kenney has claimed her brother, from Earl Shilton in Leicestershire, was put in handcuffs when he was taken by police for treatment.
While in the hospital emergency department, she has alleged her brother was given a sedative and his heart subsequently stopped beating.
“They managed to stabilise him and put him into an induced coma, but he never came out of it,” she added.
A spokesperson for University Hospitals Coventry and Warwickshire (UHCW) NHS Trust said: “We have received a formal complaint, which we will respond to accordingly, whilst supporting any requests for assistance from the IOPC.”
Leicestershire Police and Warwickshire Police are being investigated by the Independent Office for Police Conduct (IOPC).
Both forces said they were unable to comment further until the investigation was completed.
A spokesperson for the IOPC said: “Our investigation began following referrals from both forces into Mr Kenney’s death and a family complaint.
“The investigation will look at the actions and decisions made by the officers in dealing with Mr Kenney during his detention, transport to and initial care at hospital.
“We will also look at the interaction between the forces, what information police provided to medical staff.”
The Warwickshire coroner’s office said it was awaiting the results of a post-mortem examination, which could take several months, before the cause of his death could be confirmed.
Ms Kenney has said the family have been left “heartbroken” by her brother’s death and she has been left confused and in need of answers.
She added: “We’ve always had each other’s backs, so when he passed away it’s been really hard, because it’s like everything’s just gone silent.”
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