Video report by ITV News Correspondent Juliet Bremner
Anthony Dawson's death in care was avoidable, a jury at his inquest found. Neglect on the part of the NHS played its part.
It has left his sister Julia feeling angry and cheated.
She told ITV News Anthony had failed by those whose job it was to protect him.
An NHS review of the deaths of hundreds of people with learning difficulties has shown Anthony was not alone.
The study, which was initiated in 2015 in response to concerns over failings in the care of patients with learning difficulties, examined 1,311 cases over an 18 month period.
Of those, only 103 patient deaths have been fully investigated and in 13 of those cases the individual's health had been adversely affected by poor care - and in some cases neglect and abuse.
Like those in the study Anthony had autism and learning difficulties.
He had difficulty communicating when he was in pain, his sister Julia told ITV News.
"He couldn't communicate when he was in pain. He couldn't communicate very much at all," she said.
He did not receive regular blood tests, and for the last 13 years he received none at all until his death from a ruptured stomach ulcer in 2015.
"Anthony had his life robbed," his sister told ITV News. "None of his medical needs were looked after."
The review found that, overall, the life expectancy of people with a learning disability falls below the average for the whole population.
On average a person in the UK can expect to live to 82, but people with learning disabilities have an average life span of just 58, the study showed