How to I get my dad to educate himself on how to care for his wife with Alzheimer's?

My dad is the primary care for his wife (my mother) who has Mild Alzheimer's. She has become very angry towards him. He does not know how to handle it. When I tell him not to try to reason with her he agrees but turns around and tries to reason with her. The way he is handling things is making her worse. What can I do? She wants him to die and go away........