Whenever I’ve met someone, or received a letter from someone, who claimed to be an atheist I’ve always tried to discover exactly why they didn’t believe in God. You might want to ask your brother the same question.
Often, I found, they weren’t really atheists at all — that is, they didn’t firmly and decisively believe God didn’t exist. Instead, they were what we call agnostics — that is, they didn’t know whether or not God exists. Unfortunately, they often were content to stay that way instead of seeking God. They were unwilling to see if Jesus’ words are really true: “Seek and you will find” (Matthew 7:7).
Others, I discovered, claimed that they didn’t believe in God, and they may even have convinced themselves that they were right. But the more I probed, the more I discovered that often their real problem was that they didn’t want to believe in God. Instead, they wanted to run their own lives without any interference from God — and no matter what evidence you presented, they were determined to leave God out of their lives. Their problem was in their wills, not their minds.
Pray for your brother; God is able to break through even the hardest heart. As God gives you opportunity, challenge him also not to have a closed mind toward God. Most of all, ask Christ to make you an example to him of God’s love and strength. Remember: “You are the light of the world” (Matthew 5:14).