When a doctor tells someone that they have Alzheimer's they should be very careful that the patient really has Alzheimer's.

I can agree on one level, and yet say that you should have your 'elder' or loved one examined by a physician that deals with geriatric issues. A 'GP" may not be qualified to make this diagnosis, but many times the opposite is true. The person will HAVE Alzheimer's and the doctor discounts this possiblity. Discuss their habits and limitations with a qualified geriatric doctor.