The father of two died in the ambulance on the way to Dunedin Hospital.
A postmortem examination found the cause of death was ''raised intracranial pressure'' due to an intracranial cyst.
Coroner Anna Tutton, of Christchurch, released a report yesterday which said Bates' death raised serious issues about the availability of medical facilities and resources at Dunstan Hospital, and she has recommended better district-wide guidelines for managing head injury cases.
Despite the recommendations, Mrs Bates was upset nobody had been held accountable for her son's death.
''As far as I'm concerned, it seems money comes before people. I can name about four people - collectively they were all at fault.
''If something bad happened to someone close to you, you would want to know whose fault it was, wouldn't you?
''I'm sorry to say my faith in doctors and hospitals is not very good at the moment.''
Other members of the family were ''absolutely ropable''.
''It was a terrible thing. It was absolutely shocking. It's been nearly three years, but honestly, it just feels like three days ago.
''When it's your one and only son, it's a bitter pill to swallow.
''He was so popular. There were over 600 people at his funeral, so that tells you something.
''He had a fantastic sense of humour.
''You could growl at him and he would just stand there and give you his cheeky grin.
''He was wonderful.''
Mrs Bates hoped the recommendations made in the coroner's report would save other Central Otago families from a similar fate.
''I'm just praying that this never happens to anybody else. I wouldn't like to see anybody go through what we've had to go through.''