Witnessing to "churched" people

We(the kids and I, Brian was sick) went to a live nativity (picture post forthcoming) today at a horse stable run by a Christian lady who takes this opportunity at Christmas to host this nativity, free cocoa, and hayrides, as an opportunity to share the gospel. After we saw the pageant and pet the animals we headed outside to the hayride, but it was full, and we ended up waiting beside a man and his little daughter. We started talking about the wind and cold, and progressed from there. By the time that we'd made it to his leaving a former denomination and becoming part of a local community church that he obviously loved, saying that that was when he came to a personal relationship with Christ, I was beginning to think that we were probably on the same page. But in our evangelism class at church this past fall, we were reminded that many churched people are not truly converted. I asked, "so when did you become a believer?", expecting a clear answer of when he had received Christ as his Savior. He answered simply that he'd always believed in God. I was beginning to be a bit concerned, so I asked my husband's favorite question, "Okay, If I were dying and had only five minutes left to live, tell me how I can know that I'm going to heaven.'' The reply? "Just open your heart, that's the best I can tell you." Our time was running out as we headed back to our cars, but I was feeling very concerned now that this man felt that he had a personal relationship with Christ apparently based on his belief in God and some experiences in feeling peace from God in specific life circumstances, but seemed could not share the basic gospel message with a seeking soul. I handed him a million dollar bill and briefly shared how the law was written on it, to teach us of our sinfulness so that we could see our need for a Savior. He told me that it was cool, and thanked me. Pray that God would open his eyes to clearly understand and accept the good news.