"That Eighteenth Summer" by Raine O'Tierney

This is the story of Oliver Hannigan, who has just graduated from high school and plans to join the military like his older brother, Benjam, did five years earlier.  However, word comes that spring that Benjam has been killed on duty oversees; this changes Oliver's life in many ways.  His parents both go a little crazy, and his mom begs him not to follow in his brother's footsteps.  And the arrival of Benjam's best friend from the Army adds to Oliver's complications.

This was a well written coming-of-age story, which takes part in Oklahoma and Missouri.  Oliver is forced to grow up quickly after the death of his only sibling, and the author makes him credible and sympathetic.  174 pages (Kindle edition).