I had a friend named Peter by Janice Cohn

I had a friend named Peter: talking to children about the death of a friend by Janice Cohn, illustrated by Gail Owens.  William Morrow, 1987.

A good book for introducing death and the funeral process as it follows Betsy's parents explaining the death of her friend Peter. It also touches on wishful thinking, as Betsy believes that it was her saying "I never want to see you again" which caused Peter's death. The illustrations show Betsy's parents comforting her. [Includes Notes for parents]