Start with high-confidence loss & grief books, then narrow by subgenre or adjacent topics.
Not Quite a Ghost
Anne Ursu
Mayday
Karen Harrington
The Tear Collector
R. M. Romero
Before the Ever After
Jacqueline Woodson
When Life Gives You Mangos
Kereen Getten
Theo Tan and the Fox Spirit
Jesse Q Sutanto
Because of Winn-dixie
Kate DiCamillo
The Trouble With Heroes
Kate Messner
How Do You Live?
Genzaburo Yoshino, Bruno Navasky