That's Christian propaganda. I remember the controversy when it happened. Some ghoulish Christian apologists exploited Flew's mental decline in his old age, and wrote a book and passed it off as Flew's, writing it in first-person like the words were his rather than his Christian co-writer's.

https://www.nytimes.com/2007/11/04/magazine/04Flew-t.html

http://richardcarrier.blogspot.com/2007/12/craig-annoyed.html