What are the motifs in Lone Survivor: The Eyewitness Account of Operation Redwing and the Lost' by Marcus Luttrell?

Family and friends are recurring ideas. Marcus felt very strongly about his family and his friends. As the book opened, he was driving across the country to talk with the families of each of his fallen comrades in person so he could tell them about the death of their loved ones, including how much they meant to him, and how they inspired him as a soldier. He thought very highly of these men both as friends and as soldiers.