bkorea,
The symptoms you mention do sound typical of AD, but they can also be indicative of many other things as Aitan mentioned. A diagnosis of AD is basically a "none of the above" so to have confidence in the diagnosis there are a lot of other paths you and the doctors need to explore first.
PBS put out a 2 hour special on AD called "The Forgetting" which is now available on DVD and airs from time to time. They have a website and it's a very informative little special. They discuss some new technologies that will eventually allow doctors to image the specific microscopic parts of the brain that are indicative of AD, but it's strictly experimental today.
PBS - The Forgetting
HBO also just aired a series of shows called The Alzheimer's Project. They are available to watch for free on their website. I have not watched them yet, but I'm sure they are very informative and a little bit more current than the PBS documentary from a few years back.
HBO - The Alzheimer's Project
Regarding whether or not to talk about the diagnosis, it is completely up to the person in question. You have to be the judge of whether or not it will be helpful or appropriate to discuss it openly. I personally believe that if you fear something and are afraid to face it you give it power and increase your fear, and facing it openly makes it more manageable. This obviously does not work for everybody.
In my grandmother's case she was in denial from the very first day in 2000 when she was diagnosed. A year or so later, out of the blue, she called my mother and took her to a lawyer to sort out all the legal matters. She spoke as little as possible the entire time and never acknowledged why they were there, and proceeded to pretend she didn't have it for the next 6 years or so.
At that point she was beginning to get very frustrated and feel very alone. She didn't know anybody else with the same problem and she was beginning to feel very stupid all the time. I got her an easy reading book that was an AD patient's autobiography, and it helped her a lot. For about a year she knew that she had AD, knew that she needed help, and more readily accepted my guidance even when she didn't understand it.
That period passed and if you ask her today she doesn't have it, doesn't need help, isn't forgetful, and is just the same as she's always been. She was doing just fine until I moved in and took over everything. Now she doesn't know where things are, can't remember how to cook, etc. It's apparently my fault, because she was doing just fine before. =-)
It would be SO helpful if people had the clarity of thought to see their illness, admit they need help, and take proactive steps. Unfortunately the ability of self diagnosis disappears very early on. Your father may have always been stubborn, but if he really has AD then he's not being stubborn in the same way as he was before. If the diagnosis of AD is correct then may not have the ABILITY to perceive the truth, and you can't just treat him as if he's being stubborn.
Long story short, I recommend testing the waters and talking about AD openly. In theory it shouldn't be any more taboo than talking about a broken finger. Be sensitive, though, and be prepared to cease and dance around the issue for the rest of his life if that's what he needs from you. Three words I can no longer use around my house are "Alzheimer's", "memory", and "forget". They're sure to trigger a frustrated and angry response every time.