When Haru Was Here by Dustin Thao

How do you say goodbye when you can't let go?
 
After the death of his best friend, Eric Ly creates imaginary scenarios in his head to deal with his grief. Until one of them becomes real, and a boy he met last summer – Haru Tanaka – walks into the coffee shop and sits down next to him.  The only thing is, nobody else can see him.
 
Eric suddenly has someone to connect with, making him feel less alone in the world. But as they spend more time together, he begins to question what is real.  Soon Eric is losing control of the very thing that is holding him together, and must confront his reality. Even if it means losing Haru forever.