Start with high-confidence loss & grief books, then narrow by subgenre or adjacent topics.
Not Quite a Ghost
Anne Ursu
Remarkably Bright Creatures
Shelby Van Pelt
Mayday
Karen Harrington
The Invisible String
Patrice Karst, Joanne Lew-Vriethoff
The Tear Collector
R. M. Romero
Before the Ever After
Jacqueline Woodson
The Guncle
Steven Rowley
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