Peter Tulloch says his 83-year-old mother Jean was put on the Liverpool Care Pathway (LCP) when she was at the hospital. Under LCP, medical staff who judge that a patient is close to death withdraw food and water while the patient is sedated.
Mr Tulloch, from Biggleswade in Bedfordshire, said he believes his mother was dying but LCP was used to speed up her death.
He now wants prosecutions and has reported the case to Bedfordshire Police who have passed it on to the Lothian and Borders force.
Mr Tulloch said that when he visited his mother at the Western, where she had been admitted with a urinary tract infection, he was surprised to find that fluids had been removed.
According to Mr Tulloch, the family were not told about the move which he believes led to her death.
A spokesman for the BMA said: "LCP is the best-known tool to manage the care of dying adults."