The Four Diamonds 1995 on netflix

Christopher Millard was 14 years old when he died of cancer in 1972. Shortly before losing his battle, Chris wrote a story about a great knight named Sir Millard who sought out the four diamonds of Courage, Wisdom, Honesty and Strength in order to be released from the grips of an evil sorceress. These diamonds symbolized the attributes that Chris believed were necessary to overcome cancer.