The Alzheimer’s Association. Information on Alzheimer’s and helpful materials for caregivers. They also have a 24/7 helpline.
The American Cancer Society provides information on everything about cancer. They have a toll free number you can call for additional information, as well as the website and extensive reading material.
The American Diabetes Association had information on Diabetes and on healthy living and ways to manage the disease.
The American Heart Association site is full of information related to heart disease and stroke and the prevention of the same.