Hi Mike, and thanks for your Share.
Finding out what a disease is actually like before visiting with a patient is great advice, not just for Alzheimer's but for other conditions as well.
As a cancer patient living with leukemia I have sometimes been appalled by rude and ignorant questions or behaviors I've encountered from people who mean well but who learned a lot of wrong things about leukemia from movies and TV shows. They often don't realize how little they know or even why they are so offensive when they think they are being "helpful" or sharing knowledge.
If you truly care about someone it should be worth taking some time to develop a basic understanding of the disease before visiting them, and to come prepared to offer unconditional support and encouragement.