He died today.

In 1976, he was nominated for the Hans Christian Andersen Award. He's written for adults as well.

https://www-svt-se.translate.goog/kultur/forfattaren-hans-peterson-ar-dod?_x_tr_sl=sv&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc
(translation of his obit, with short video)

Hans Peterson, one of Sweden's most prolific children's and youth writers, has passed away. From his debut in 1945, he wrote nearly 250 books, including many easy-to-read stories for adults.

Hans Peterson, born in 1922, began his career as an electrician. When he debuted in 1945 with "Stina and Lars på vandring" he participated in a competition won by none other than Astrid Lindgren who had written her first book about Pippi that same year, says Lina Nordstrand, Hans Peterson's granddaughter who was also one of his many publisher.

With "Liselott och garaffen" (1962) he won Rabén & Sjögren's children's book competition. Among his many titles is also "I'm going to have children!" (2005) which deals with a teenage pregnancy.

The conviction of the importance of children's and young people's reading ability made Hans Peterson also one of the first easy-to-read authors for adults. In total, he wrote roughly 250 books, according to Lina Nordstrand.

- It sounds incredible, but he wrote until he was over 90 years old. He is a big name in the book industry if you worked there from the 1960s to the 80s, but that is a long time ago now, she says.

"Loneliness, love, warmth are the essential components of life, whether you are a child or a so-called adult." That's what Hans Peterson himself said about the themes in his books in a quote that is reproduced on Rabén & Sjögren's website. Over the years, he received, among other things, the Nils Holgersson plaque, Germany's major children's book prize and the Astrid Lindgren prize. Hans Peterson also wrote Christmas calendars such as "Julbåten Juliana" in 1961 and "A small town at the turn of the century" in 1966.

"Joel is dead" from 2016 was Hans Peterson's last book.

(end of obit)

He lived in Gothenburg, Sweden. Most of his work was written pre-1980.

One series he wrote centers on a boy named Magnus.

https://www.goodreads.com/book/show/15728770-erik-and-the-christmas-horse
(review of a 1957 book, with a photo of one illustration)
"A local delivery man is touched by a young boy's concern that he might be homeless, so he takes the youngster home to meet his wife. A sweet, touching story with beautiful illustrations by Ilon Wikland."

https://www.kirkusreviews.com/search/books/?q=hans%20peterson&sf=t
(eight Kirkus reviews)

https://alchetron.com/Hans-Peterson
(from 2018 - a photo plus a video of a piano-and-violin tribute song?)

Most of what I wrote in 2012, on his 90th birthday:

He began writing in 1949. "Liselott and the Goloff" was included in
the Hans Christian Andersen Honor List, 1964. He received the Astrid
Lindgren Prize in 1971.

https://www.google.com/search?num=10&hl=en&site=imghp&tbm=isch&source=hp&biw=800&bih=403&q=%22hans+peterson%22+books&oq=%22hans+peterson%22+books&gs_l=img.3...2328.5750.0.6234.21.17.0.4.0.0.109.1045.15j2.17.0...0.0...1ac.1.LbfoYArO-0s
(a few book covers)

http://en.wikipedia.org/wiki/Hans_Peterson
(includes more awards and his adult books)

http://imdb.com/name/nm0677180/filmotype
(TV filmography)

WRITINGS BY THE AUTHOR
Children's books; all Swedish editions published by Raben & Sjoegren
(Stockholm), except as indicated:

Magnus och ekorrungen (also see below), 1956, translation by Madeleine
Hamilton published as Magnus and the Squirrel, Viking, 1959.
Magnus, Mattias och Mari (also see below), 1958, translation by
Marianne Turner published in England as Magnus and the Van Horse,
Burke, 1961, published as Magnus and the Wagon Horse, Pantheon, 1966.
Magnus i hamn (also see below), 1958, translation by Turner published
as Magnus in the Harbor, Pantheon, 1966.
Naer vi snoeade inne, 1959, translation by Irene Morris published as
The Day It Snowed, Burke, 1969.
Magnus i fara (also see below), 1959, translation by Turner published
as Magnus in Danger, Pantheon, 1967.
Petter Joensson hade en gitarr, 1959, adaptation by Kay Ware and
Lucille Sutherland published as Peter Johnson and His Guitar, Webster,
1961, stage adaptation by Turner, Burke, 1965.

Naer vi regnade inne (title means "The Day It Rained"), 1960.
Gubben och Kanariefaageln, 1960, adaptation by Ware and Sutherland
published as The Old Man and the Bird, Webster, 1964, stage adaptation
by Marianne Helweg, Burke, 1966.
Maens och mia, 1960, translation published as Tom and Tabby, Lothrop,
1965.
Magnus och skeppshunden Jack, 1961, translation by Turner published as
Magnus and the Ships Mascot, Burke, 1964.
Lille-Olle och sommardagen, 1962, adaptation by Ware and Sutherland
published as Benjamin Has a Birthday, Webster, 1964.
Liselott och Garaffen, 1962, translation by Annabelle Macmillan
published as Liselott and the Goloff, Coward, 1964.
Det nya huset, 1962, adaptation by Ware and Sutherland published as
The New House, Webster, 1964, stage adaptation by Helweg, Burke,
1966.
Mick och Malin, 1962, translation published as Mickey and Molly,
Lothrop, 1964.
Boken om Magnus (title means "A Book about Magnus"; includes Magnus
och ekorrungen, Magnus, Mattias och Mari, Magnus i hamn, Magnus i
fara), 1963.
Haer Kommer Petter, 1963, translation by Turner published as Here
Comes Peter, Burke, 1965.
Hunden Buster, 1963, translation published as Brownie, Lothrop, 1965.
Stina och Lars rymmer, 1964, translation by Patricia Crampton
published as Stina and Lars in the Mountains, Burke, 1970.
Petter kommer igen, 1964, translation by Turner published as Peter
Comes Back, Burke, 1966.
Naer hoensen blaaste bort, 1964, translation by Morris published as
The Day the Chickens Blew Away, Burke, 1970.
Liselott och de andra, 1965, translation by Morris published as Lisa
Settles In, Burke, 1967.
Den nya vaegen, 1965, translation by Morris published as The New Road,
Burke, 1967.
Petter klarar allt, 1966, translation by Evelyn Ramsden published as
Peter Makes His Way, Burke, 1968.
Bara Liselott, 1967, translation by Morris published as Just Lisa,
Burke, 1969.
Den nya bron, 1967, translation by Morris published as The New Bridge,
Burke, 1969.
Sara och sommerhuset, 1967, translation by Morris published as Sara in
Summer-time, Burke, 1973.
Expedition Snoestorm (title means "Expedition Snowstorm"), 1968.
Jag vill inte, sa Sara, 1968, translation by Morris published as I
Don't Want to, Said Sara, Burke, 1969.
Lill-Anna, Johan och den vilda bjoernen (title means "Lill-Anna, Johan
and the Wild Bear"), Gebers (Stockholm), 1968.
Magnus Lindberg och haesten Mari, 1968, adaptation by Christine Hyatt
published as Eric and the Christmas Horse, Burke, 1969, Lothrop,
1970.
(With Harald Wiberg) Naer Per gick vilse i skogen, 1969, translation
published as When Peter Was Lost in the Forest, Coward, 1970.

Franssonsbarna i Faagelhult (title means "These Children in Bird-
Cottage"), Gebers, 1970.
Aake gaar till sioess (title means "Aake Goes on Board"), Gebers,
1970.
Ett lejon i huset (title means "A Lion in the House"), 1970.
Pelle Jansson, en kille med tur, 1970, translation by Hanne Barnes
published as Pelle Jansson, Burke, 1974.
Sara och Lillebror, 1970, translation by Morris published as Sara and
Her Brother, Burke, 1973.
Pelle Jansson, en kille mitt i stan, 1971, translation by Barnes
published as Pelle in the Big City, Burke, 1974.
Radovan och Ritva (title means "Radovan and Ritva"), 1971.
Pelle Jansson, en kille som inte ger sig, 1972, translation by Barnes
published as Pelle in Trouble, Burke, 1976.
Rut och Rickard (title means "Rut and Richard"), 1972.
Var kommer bullen ifraan? (title means "From Where Comes the Roll?"),
1972.
Dagen naer allting haende (title means "The Day Everything Happens"),
1973.
Den nya bilen (title means "The New Car"), 1974.
Lantgaarden (title means "The Modern Farm"), 1974.
Vilse i fjaellen (title means "Lost in the Mountains"), 1974.
Den stora snoestormen, 1975, translation by Barnes published as The
Big Snowstorm, Burke, 1976.
Jakten paa Janne (title means "The Hunt for Johnny"), 1975.
Malin paa en oede oe (title means "Malin on the Waste Island"), 1975.
Veckan Anna och Vlasto foersvann (title means "The Week Anna and Vlast
Escaped"), 1975.
Varfoer blir det saa (title means "Why Does That Go So?"), 1975.
Maja-Lena gaar till morfar (title means "Maja-Lena Going to
Grandfather"), 1975.
Faagelpojken (title means "The Birdboy"), 1976.
Dagen innan vintern kom (title means "The Day before Winter Comes"),
1976.
De fyra hemloesa (title means "The Four Homeless"), 1977.
Dagen naer Simon flyttade (title means "The Day Simon Removed"),
1977.
Malin har en hemlighet (title means "Malin Has a Secret"), 1977.
Kaera Alberta (title means "Dear Alberta"), 1977.
Huset (title means "The House"), 1977.
Resan (title means "The Trip"), 1977.
Aron heter jag (title means "My Name Is Aron"), 1978.
Malin aer indian (title means "Malin Is an Indian"), 1978.
Jag, Alberta (title means, "I, Alberta"), 1978.
Aentigen Alberta (title means "At Last, Alberta"), 1979.
Dagen naer Simon strejkade (title means "The Day Simon Goes on
Strike"), 1979.

Turns out it was suicide, but I can't find anything more.