Hearts Divided (The Founders #5)
Robert Vaughan

Finally, after having his hairbreadth adventures, Danny O’Lee finds his beloved brother—fighting on the other side—at the bloody Battle of Shiloh, a turning point in the little known Civil War in the West.
There, a hero is born, a villain unmasked and a loved is renewed, while the Union finds a general in an obscure, cigar-smoking, whiskey-drinking sphinx of a man names U.S. Grant.