How should I handle a situation of potential stolen valor?

I live right out side of post.(fort bragg) I have this aquatince that I run into all the time. He tells me stories about his time in service. He has shown his veterans card. But recently I was talking with warrant officers outside of my apartment complex and he called this individual out on multiple lies about his time in service. And he informed me that him lying about aspects of his duty could be stolen valor. If this individual approaches me should I do or say anything or just let it go. I dont have nearly enough time in service to know how to handle situations like this.