Thanks for writing.
Alzhiemers patients longevity depends on age of disease onset. How long a person with Alzheimer's will live is highly dependent on the person's age at the onset of the disease as well as what medical problems the person is experiencing in addition to Alzheimer's. Those with multiple medical conditions tend to die sooner than those who have no other physical problems. Individuals with Alzheimer's disease often die of a medical complication such as pneumonia
or the flu
. However, Alzheimer's is fatal -- if there are no other complications, the person will die when all bodily systems fail because of the disease.
Hope this helps