O.K. Again, more questions.
1. Can someone didn't have faith...then get faith?
2. If the answer is yes, what is different in them.
3. If there is a difference, is this the only explanation for the change? Can it be something else?
Based on what I know from atheist family members (from my grandfather through to my husband). It is not a matter of faith, it is a matter of belief. They find it impossible to believe in the concept of God, no matter how God is depicted as acting. It's a matter of not being able to believe in the concept.
To me, these are the true atheists, not the atheists who can present numerous reasons why they
don't believe because of all the things they think God did, or all the things they say God has not done. They have
reasons, and can come up with a million more. My grandfather, you might say, was surrounded by people who did believe, and he did not think people who believed were simply imagining God. They 'saw' something or 'had' something that believing was as natural as breathing. It was real. He understood that. He didn't know
why he didn't believe, he just knew that he didn't. My own husband is much the same. He says if he is standing before God his question would be, "Why couldn't I believe?" He feels his own offering would be, he couldn't pretend--he could at least offer God that much....no pretense.
Faith: One can live by faith that doing the right thing is best, it brings better results, a better life. There have been times my husband and his (atheist) brother have been in the midst of a family problem where they came to me, admitted they were at a complete and total loss, and could I help them through prayer. Through prayer came insights, which I related to them of what they should try. They both looked at me in disbelief, and frankly told me if that was the best that came through prayer, why bother. However, as they were already at rock bottom (perhaps underneath rock bottom) they gave that prayerful solution a try. It worked and worked well. Of course, in the next minute they were saying it came through my own wisdom, they should have thought of it themselves, no God involved.
All this to say my answer is, "I don't know." My experience is that belief and faith are tied together.