Who is Noah from The River Between Us and what is their importance?

Noah is Tilly's twin brother. He is said to be the quieter of the two, and he is described as hard working and devoted to family. Noah becomes the man of the house at a very young age, his father having disappeared several years before the narrative begins. He is devoted to Delphine, but he is unable or unwilling to reveal his feelings for her until the dance on the showboat, shortly before he goes off to war.