Flew is 81 years old, has been a practising atheist for 50 years, and 4 years ago he gets interested in religion.
Why doesn't anyone think that as Flew gets closer to the grave, and the realization of his mortality, he'll get even more religious?
Because in the articles in which Flew described his turn towards Deism, he announced that he'd come to the conclusion that he believed in an absent, uncaring God, and that he thought the idea of an afterlife was nonsense.
I believe historically you'll find the older a person gets, the less likely he is to change religious views.
Many people become Christians as children and young people. Much fewer over 65 make the transition from nonbeliever to believer. Why? Because you have to make a radical re-commitment to your entire world-view and admit you've been wrong all along.
As people get older, they are more set in their thinking and less willing to do that despite the fact of their impending mortality. That would admit they have believed a lie or ignored the truth all their lives. Oh, many may think they are going to Heaven, but they live on false hopes and wishes, nothing else. They have no assurances, except things superficial like, "I've always been 'good'" or "God would never be so cruel as to send me to hell", or "we're all God's children"! These shallow views stem from unBiblical teachings and popular culture, and are prevalent even among a lot of liberal churches as well as agnostics.
They are hopes and a form of "faith". Biblically false ones.
If interested, read the book, More Than a Carpenter, by Josh McDowell. Like Flew, he was an atheist, trying to prove that God didn't exist and Jesus was definitely not the Son of God or a Saviour. His research led him to believe otherwise.
Everything everyone has ever done has occured on the way toward the grave.