Only one in five dying patients have their medication reviewed in the last day of their lives in some hospitals, while in others as few as 10% of patients are assessed to see whether they need help with drinking, according to an end-of-life audit.
The report by the Royal College of Physicians also found one in 20 family members are not informed their loved one is about to die, even when a medic has recognised the patient is nearing the end of their life.
Close friends and family of patients who are dying are not always being told about decisions about their loved one's care, the audit found.
The two questions everybody wants to know about their relative is 'are they dying?' and 'how long have they got?' In the five years from my son's diagnosis to his death, everybody was dealing in euphemisms because we were in denial and nobody said 'your son is dying'. Those discussions are really important.
In the majority of deaths reviewed, medics had included a "do not resuscitate" order in the patient's notes. But in 18% of cases these orders were not discussed with family members.
Mr Bonser added: "A consultant said to us: 'In the case of heart attack, we will not attempt to resuscitate your son'. That wasn't a discussion. All we heard was 'there is something we can do and we are not doing it'. That is a very difficult message to get across."
Amanda Cheesley, from the Royal College of Nursing, said all hospital staff - from porters, to catering staff, nurses and doctors - who have contact with a dying patient should be trained how to communicate with them.
The report, a systematic review of care of 9,000 patients at the majority of hospital trusts across England in 2015, highlights "unacceptable" variation in some aspects of care, including:
In some trusts as few as one in five dying patients have their medication reviewed in their last 24 hours
In others, as few as 10% of patients were assessed to see whether they needed help with drinking. Across the country there was no documented assessment of the patient's ability to drink in the last 24 hours of their lives in a third of cases.
Just 31% of patients were reviewed by a member of a specialist palliative care team after being admitted to hospital. Only 11% of trusts had specialist palliative care on offer 24/7.
Professor Sam Ahmedzai, chair of the RCP End of Life Care Audit steering group, said the audit had generally shown improvements in the quality of care patients receive at the end of their lives.