Has anyone done any digging on wearing the cross as a piece of jewelry?

My best friends son was born with 12 different heart defects. She was told 3 times he would not make it through the night. I was raised Catholic (but had since rejected the church) She was complete atheist. One difficult day I went to the chapel in the hospital and prayed for him. I made a deal with God that if he let him live I would do everything in my power to help her find God. I didn't know how - She was ANTI God. I went back to ICU and nervously gave her a small silver cross on a chain for him. She immediately put it on him. Multiple surgeries later he is now 26 And she has found God. (5 years later) Not only was he saved but she was saved too.