What do Mike and his grandmother give each other in the story the mustache?

In "The Mustache" by Robert Cormier, Mike and his grandmother share a meaningful exchange that revolves around honesty and understanding. Mike gives his grandmother a heartfelt confession about the changes he is going through as a teenager, while she offers him wisdom and insights about growing up. Their interaction highlights the bond between them and the importance of communication in relationships. Ultimately, they both give each other a deeper understanding of themselves and each other.