In I Still Believe, how did Jeremy and Melissa know that the cancer came back and was terminal?

Long story short, I got a phone call from a friend," says Camp. "They're like, 'Hey, Melissa is in the hospital. She has cancer,' and so I went down to visit her, and I walked in, and [similar to the movie] she said, 'Jeremy, I've been sitting here thinking. If I die from this cancer, but if even one person gives their life to Jesus, then it's all worth it.'" Camp said that those words had an enormous impact on him, that if she was able to bring even one person closer to Christ, then her life was all worth it. Their love for each other was quickly rekindled. "I just knew that she was the one for me, and she felt the same way." They ended up getting married, and according to Camp, had "an amazing, beautiful wedding." -WAY Nation

It can be peer pressure, also when they’re going through a lot of stuff at home