So far, all I've found is this small notice (but at least there's a photo).

https://www.towntopics.com/wordpress/2022/02/16/obituaries-2-16-2022/

Diane Sherman-Levine, 93 years of age, passed away on February 6, 2022. A former resident of Princeton, NJ, she was a beloved wife, mother, grandmother, and great-grandmother. She is survived by her three children, four grandchildren, and one great-grandchild.

Diane was an author, holistic healer, and a longtime humanitarian. Her love and laughter will be very much missed.

Services are being held privately.

https://groups.google.com/g/rec.arts.books.childrens/c/ENsH402D1VM/m/9f8DdsSvBQAJ
(birthday post from 2018)

From April 2018:

"Diane Sherman-Levine has been a channel, a healer, a medium, and a teacher for over thirty years. A graduate of Mt. Holyoke College, she left a successful writing career when her intuitive abilities began to surface, and studied healing and mediumship widely, in the U.S. and Britain. Her channeled material has appeared in many publications, and a description of her work appears in the book “Healing Tales” edited by Stanley Krippner (Puente Publications 2007) who is a well-known psychologist and an explorer of consciousness. She has given many presentations and workshops for a variety of organizations and has a healing practice in Princeton, N.J. where she also gives readings in person or by phone and holds classes in the development of psychic awareness and the ability to access spiritual gifts..."

https://www.google.com/search?biw=1266&bih=850&tbm=isch&sa=1&ei=FogJXLTZE9Dl_QbdnbSQBQ&q=diane+sherman+books+elf&oq=diane+sherman+books+elf&gs_l=img.3...10541.11364..11528...0.0..0.84.276.4......1....1..gws-wiz-img.iR7-mfPVTS8
(some book covers)

https://www.goodreads.com/author/show/1083412.Diane_Sherman
(reader reviews)

From "Contemporary Authors":

"Contributor of stories, articles, poems, and plays to Child Life and other children's magazines; contributor of science articles to adult magazines."

WRITINGS BY THE AUTHOR:
Children's books; all published by Rand McNally, except as noted:

Little Skater, 1959.
My Counting Book, 1960.
Myrtle Turtle, 1961.
Jumping Jack, 1962.
(With Shirlee Newman) About the People Who Run Your City, Melmont, 1963.
(With Newman) About Canals, Melmont, 1964.
You and the Oceans, Children Press, 1965.
Nancy Plays Nurse, 1965;
All Around the City, 1967.
The Boy from Abilene: The Story of Dwight D. Eisenhower, Westminster, 1968.

My Oak Tree, 1973.
People Who Work at Night, 1973.
The Xmas Snowman, 1977.