A terminally ill man was found in pain, dehydrated and deeply distressed at a hospital in Greater Manchester, the Health Service Ombudsman has found.
The patient, identified only as Mr D, was being treated for stomach cancer at the Royal Bolton Hospital.
Wanting to die at home, he was discharged. His family then discovered he did not have the right pain relief. He died three days later.
The hospital admitted they had failed Mr D and have apologised to his family.
The Health Service Ombudsman carried out an in-depth review of 10 cases, including Mr D's.
It found the NHS has been failing to treat elderly patients in England with care, dignity and respect.
People aged over 65 suffered unnecessary pain, neglect and distress, it added.
The government has admitted improvement was needed.
Mr D's daughter said: "His mouth was all dry and sore. His mouth was like a piece of dried up liver. It was awful.
"They obviously had got him ready for discharge because his bag was packed and on his bed and his bed had been stripped.
"They had taken his drip out of him - the tube had fallen on to the floor and had leaked.
"It turned out they had got him ready for discharge at 6am that morning and hadn't been near him since.
"He wanted the toilet. They had given him a panic button but they had tucked it behind his back and he couldn't reach it.
"He couldn't get anyone's attention because he was shut away behind the curtain."
Deputy Health Service Ombudsman Kathryn Hudson said they were "extremely concerned" about Mr D's case, which had happened six years ago.
She said it highlighted a failure to meet the basic standards of care, not treating a patient as an individual, and not understanding the relationship with the family.
She said Mr D's family had complained to the hospital twice, and raised it with the Healthcare Commission before taking it to the ombudsman.
In a statement, the Royal Bolton Hospital said: "The ombudsman's report confirms our own investigation and the subsequent Healthcare Commission report.
"The trust fully accepts that regrettably we failed in our care of this gentleman but we also did not provide his daughter with evidence of the changes we made.
"We would like to repeat our apologies to her for all of this."
The hospital said it had improved its procedures with personal care, risk assessments and discharge arrangements since Mr D's case.