A woman says a hospital nurse was so shocked at the condition of her mother she said: "Oh my God, what did they do to your mother in that care home?".
Catherine Cawte has been giving evidence at an inquest in Newport into the death of her mother Dorothea Hale.
She was a resident at Grosvenor Care Home in Abertillery, Blaenau Gwent, from July to November 2006.
Mrs Hale, who was severely dehydrated and malnourished, died aged 75 in hospital on 6 January 2007.
Her death was investigated as part of Operation Jasmine, the £11.6m operation into alleged abuse at six care homes in south Wales.
It spanned seven years, looked at 63 deaths and took 4,126 statements but no-one was prosecuted.
In March an inquest found residents at another of the homes investigated - the Brithdir care home in New Tredegar - were "dehumanised" by staff and the standards of care were "wholly inadequate".
Ms Cawte told the inquest: "I can remember being there with my dad and brother and waiting for some time and remember a nurse coming in to see us and saying words like: 'Oh my God, what did they do to your mother in that care home?'
"'She has pressure sores and her PEG [percutaneous endoscopic gastrostomy] feeding tube is filthy and blocked.'
"I remember that being the focus and mum wouldn't last the weekend because she was in such poor health.
"We were informed she was severely dehydrated and severely malnourished. That was the first we heard of the pressure sores."
Ms Cawte said a consultant said Mrs Hale's pressure sores were "the worst he'd ever seen".
Mrs Hale went to live at Grosvenor Care Home in July 2006 after having a severe stroke just days after having cardiac surgery,
But Ms Cawte said from her first visit she felt her mother was not happy in the home.
"I remember walking in and seeing my mum who looked a completely different person," she told the hearing.
"She'd aged already. She was crying - she looked very sad and forlorn. She would have never wanted to go into a care home."
Ms Cawte, who is a registered nurse, said her mother would "sit in the same chair, day in day out".
She told the inquest she did not tell staff at the home about her profession at first because she "didn't want people to think I was judging them".
In September 2006, she said staff told her that her mother was being cared for in bed because she had a pressure sore.
She said she asked to look, revealing she was a nurse, adding: "It wasn't anything I was hugely worried about. The skin was a little bit broken. I wasn't concerned that it couldn't be treated and healed."
Before long, the family were told the sore had healed and Mrs Hale returned to her routine of sitting in a chair in the home's lounge, her daughter said.
Ms Cawte said at the end of October her mother was again back in bed and she was told her mother had diarrhoea.
"There was an horrendous smell in her room," she said, describing how a fan was on, air freshener had been sprayed and the windows were open.
Ms Cawte told the inquest she later came to believe that the smell had been coming from a pressure sore on her mother's sacrum, at the base of her spine - something the family said they knew nothing about.
She said by mid November her mother's condition had become worse and she insisted staff call the GP, which led to Mrs Hale's admission to Nevill Hall hospital.
"She was dying before my very eyes" Ms Cawte told the inquest.
Ms Cawte said her mother had been her "best friend" and that her grandchildren "idolised" her.
She described her mother as "incredibly knowledgeable, fun and at times a little crazy".
The inquest into Mrs Hale's death is expected to last for four weeks.