Alzheimer's or something else?

I live with a 65 year old man, that I am curious about.

he has an online business and many times he forgets to send in orders or email the customer tracking numbers, also in the car he'll be driving and totally forget where he is going. He routinely loses credit cards and other important items he has put in the same place for years. He leaves his cell phone everywhere. I tell him I have an appointment an hour later he completely forgets I have it and he is becoming very quick to anger. He is sleeping a lot more then normal as well. I am worried about him.

It does sound like it can be some type of Dementia, although Dementia is only an umbrella term for many memory/cognitive diseases, including Alzheimer's. It can sometimes also be caused by underlying medical-health problems, not related to Dementia, certain medications or vitamin deficiencies. Best way to know for sure is to have this gentleman see a Neurologist or Psychiatrist, in order to get a diagnosis. Diagnosing Alzheimer's is done by ruling out all other possible causes and a complete brain scan (MRI or CT scan) is needed for diagnosis.
Good luck, and hope this was helpful to you
-Dan.