Lotz, the daughter of evangelist Billy Graham and the award-winning author of nine books, describes the change in her latest book, called "The Magnificent Obsession." (excerpt)
In an interview Tuesday with the Early Show co-anchor Harry Smith, Lotz said her father, who will be 91 years old this fall, is "doing very well."
Although he has some physical challenges due to old age, she said, "His mind is clear and he's gentle and loving."
Lotz' latest book is based on Abraham from the Bible.
"He became my mentor 33 years ago," she said, "and I was studying Genesis and read his story and it's like he walked off the pages of the Bible into my life. And one reason is because he had a stirring in his heart, yearning for something more than what he was experiencing.
Lotz went on to discuss her life's mission and how being the daughter of Billy Graham was both a blessing and a challenge.
To hear more about Lotz' faithful journey, click the Play button below: