Yankee Belles in Dixie, Bonnets and Bugles Series by Gilbert Morris and published by Moody.
Jeff and Leah are growing up fast. Jeff, a drummer for the Confederate Army, is only fourteen, but he's fighting a man's war. A war that has taken his family from him. Fortunately, Leah's encouragement softens the pain, and her family fills him with hope and strengthens his faith.