Russell Jenkins, 52, died after a minor injury became infected and he shunned conventional medical treatment, as previously reported in The News.
His parents have accused his partner Cherie Cameron, a former nurse who turned to alternative medicine, of failing in the duty of care she owed to their son.
A High Court judge heard how both Cameron and Mr Jenkins believed in regularly checking with their 'inner being' on how to live their lives.
Mr Jenkins injured his left foot in April 2007 after treading on an electrical plug at his home in Lorne Road, Southsea. He developed an inch-long ulcer.
But Mr Jenkins said his 'inner being' had told him not to go to hospital. Cameron did not seek medical help for her partner either.
Mr Jenkins, who ran the Quiet Mind Centre from his home, instead tried treating his wound with honey - an ancient remedy for the treatment of infected wounds.
But his condition deteriorated and the gangrene spread to his leg and he died.
Doctors said that if Mr Jenkins had sought help just a few hours before he died he could have been saved.
His parents Donald and Eileen Jenkins say Cameron should have helped their son.
Their lawyers argued that she was an experienced theatre nurse who ought to have known that death was inevitable Mr Jenkins did not receive antibiotics.
They also asked Mr Justice Pitchford to rule that David Horsley, coroner for South-East Hampshire, should have recorded a verdict of 'unlawful killing' at the November 2008 inquest.
Mr Horsley instead recorded a narrative verdict. He said: 'At no stage following the injury to his foot did Russell Jenkins or anyone else on his behalf seek or obtain conventional medical advice or treatment for his condition. In consequence, Russell Jenkins's condition was inappropriately and ineffectively treated by himself and by others and led to his death.'Mr and Mrs Jenkins, of Heol Isaf Radyr, Cardiff, want a fresh inquest.
The judge will give his decision in writing at a later date.
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