You can address any complaints you may have directly to the medical and paramedical staff accompanying your loved one or make an appointment with the department managers (head of department, paramedical staff) to discuss them. Each hospital also has a user exchange service that you can contact.
A diary: A diary is ideally a document open to all. So everyone can write in it but also read the content. If you wish to share intimate thoughts, private emotions, or comments that may offend other journal editors, please feel free to write them on loose paper and place them in a sealed envelope that you can stick in the notebook, always with the current date, in order to respect the chronology, which will be important for the patient in his quest for memory. The Lifemapp-logbook application, which is secure and designed for this purpose, makes it possible to create confidentiality circles and to write private messages that can only be viewed by the patient. Feel free to ask the nursing staff about the application.
A medical record: In order to respect professional secrecy, entries should not include specific diagnostic details. If the patient felt the need, he or she could ask the hospital director to retrieve his or her hospital report, or even a copy of his or her medical file, and possibly make an appointment with a doctor in the department to obtain all the explanations he or she wanted.