The Manchester Arena terrorist bombing of 2017 has claimed a 23rd victim, relatives say.Adam Regan-Brooks had been walking towards the foyer of the venue when suicide bomber Salman Abedi detonated explosives in a backpack wickedly loaded with nuts and screws as shrapnel.Twenty-two were killed, mostly young fans of popstar Ariana Grande, struck as they left after her concert.Mr Regan-Brooks, then a sixth-former, escaped physically unscathed - but he had to walk through the horrific scene as he helped a shocked friend out.His mental health deteriorated afterwards and he made several suicide attempts.He was found dead in May, aged 27, at the home in Oldham he shared with his husband, shortly after the ninth anniversary of the massacre.An inquest is yet to happen, but relatives fear he killed himself - ultimately as a result of the terror attack.Mr Regan-Brooks' sister Hannah Brooks, 33, told the Sunday Times: 'He would still be alive if not for the bombing. It's killed him too. Adam Regan-Brooks was a sixth-former when he went to the Ariana Grande concert in Manchester which was targeted by a suicide bomber'The 22 people who died, I'm sure their families would give anything to have nine more years with them the way that we've had with Adam.'But no one remembers the ones who have passed on afterwards. Some people didn't properly come home.'They are still living with it, and those people get lost.'Ms Brooks, a mortgage advisor, went on: 'I always hoped that he would cross over from being a victim to a survivor. He just never got to that point.'She said before the bombing he had been a lively teenager, who 'loved big gatherings'.He also played several instruments including the piano, and made up his own songs.And he 'loved Ariana Grande', so was keen to see her in Manchester. He found himself caught up in one of Britain's worst ever terror attacks.Ms Brooks saw a newsflash and spoke to him by phone within minutes of the blast.As he walked through the appalling scene, he told her: 'I've got people on me.' Mr Regan-Brooks 'loved' American singer Ariana Grande, whose 2017 concert in Manchester was targeted by Salman Abedi in an attack which killed 22 peopleMs Brooks said last week: 'He was incredibly lucky he'd not been there a minute or two earlier. But to see the immediate aftermath of the detonation, and have to walk through that.'She said Mr Regan-Brooks was staying with his older sister Naomi at the time, and hardly spoke, ate or left his bedroom for the following three weeks.He would cry at night and need someone in the room with him to get to sleep, unable to forget the bomb-blast he 'kept seeing over and over'.Then he began a new phase, involving heavy drinking and long nights out. He left his job in a care home and went on benefits.Compensation he received along with other survivors, of £10,000 in his case, was spent in months.As 2017 drew to a close, he had spoken of suicide, and was diagnosed with Post Traumatic Stress Disorder, and sectioned under the Mental Health Act - with his psychologist blaming the bombing.Suicide attempts followed over the years, and his sister felt not enough appropriate therapy was available. He suffered panic attacks in large crowds.In April 2022 a suicide attempt led to him requiring lengthy surgery, and needing a wheelchair.Mr Regan-Brooks' husband Michael, 34, who married him four years after the bombing, said: 'He did suffer a lot of survivor's guilt, and always said he wished he hadn't left, and had stayed there to help people.'He urged others still suffering the after-effects of the bombing to seek help.