Dementia is a progressive, incurable disease which is uniformly fatal. Many people say they would rather die than “lose their marbles”. In this respect dementia can be perceived as worse than many purely physical illnesses, which are not perceived as threatening the essence of an individual’s personhood. Dementia can thus be a devastating and difficult diagnosis to communicate.
This is not always the case though. Some people minimise the symptoms of dementia, regarding them as normal “forgetfulness” related to ageing, even when it becomes clear to health care workers that the problems are in fact not part of normal ageing.
Thus there are some personal and cultural issues that you may need to consider in communicating this diagnosis to Dr Zheng.
It is possible that his family might not wish Dr Zheng to know about the diagnosis. It is also possible that Dr Zheng may not wish to know either! Some people believe that a person is entitled to be protected when they are ill. They believe that discussing the reality of the disease may make the patient suffer more than they are already suffering as a result of illness. The more severe the illness, the greater the need for protection. This belief is cited as common in Chinese culture. In contrast, Western traditions usually indicate honesty in communicating a diagnosis. You can see that (well meaning) honesty could be perceived as unkind by some patients and their families. These issues can be even more relevant in the late stages of dementia. Some people feel that to tell someone he or she is dying is not only rude but dangerous. They fear that openly acknowledging the possibility of imminent death is courting bad luck and will make the person despair and die sooner.
Muller JH, Desmond B: Ethical dilemmas in a cross-cultural context-A Chinese example, In Cross-cultural Medicine-A Decade Later [Special Issue]. West J Med 1992 Sep; 157:323-327)