The hard fact is that all you can do is pray.
If a person does not believe in religion, then using religion as a reason will not work. A brief example from a class I taught where the topic was gender roles and feminism. A student who had identified himself as an evangelical Christian quoted the verse about wives being submissive to their husbands to justify the role of women as homemakers and mothers and not working outside the home, etc.
I decided to play “devil’s advocate”, so I asked the following questions and made the following statements: “I don’t believe in your God. Why should I have to live by what YOUR God says? Why should the laws in MY country have to conform to YOUR religion’s teachings when I don’t believe in what your religion teaches? Sure, you could get a majority of YOUR kind to pass a law to say whatever you want and threaten me with prison if I don’t comply with the teachings of YOUR God and religion, but you can only change my behavior, not what’s in my mind and heart – and I don’t believe in YOUR God. So you can threaten me like a three-year-old with punishment but you won’t open my heart to YOUR God.”
He was silent except to say that I would be damned for eternity. I responded “You don’t get it. I don’t believe so the fear of hell has no power to change me one iota.”
I concluded by saying to him and the class that this is the argument that people of faith will have to encounter or choose not to encounter. I added that the amount of people who consider themselves pro-life has actually increased a small amount over time…and some theorize this is due to better ultrasound so people hear the beating heart earlier than before and are moved. Notice, that I did not say anything about God or religion in that statement.
In short, religious people need to realize that there is another mindset out there and have to learn to think like others think.
I hope that helps