Sentence structure with the verb "erfüllen"

Question

I found the following sentence in a children’s book „Feenzauber und Schweineglück“ by Sophie Schmid.

Es war einmal eine gute Fee, die jahrein, jahraus den Kindern ihre Wünsche erfüllte.

My interest is in the sentence fragment „den Kindern ihre Wünsche erfüllte.“

Is this some kind of a dative form of the genitive with the „von“ missing before the „den Kindern“? Or is this some completely different structure? I initially thought that erfüllen had a straightforward transitive form when used in the sense of "to fulfill".

Answer 1

Usually, the expression

Sie erfüllt den Kindern ihre Wünsche.

simply means

Sie erfüllt den Kindern die Wünsche.

Here, the dative form „den Kindern“ is the Dativobjekt (indirect object):

Das gehört den Kindern.
Sie hilft den Kindern.
Sie erfüllt den Kindern einen Wunsch.
Sie erfüllt den Kindern alle Wünsche.
Sie erfüllt den Kindern ihre Wünsche.

However, the expression might give the impression that the dative form „den Kindern ihre Wünsche“ is used as a colloquial replacement for the genitive form „die Wünsche der Kinder“:

Sie erfüllt die Wünsche der Kinder.

According to Duden – Richtiges und gutes Deutsch, such expressions that are liable to make a wrong impression should be avoided.
For example, instead of

Er holte dem Kind seine Puppe aus dem Wasser.

write

Er holte dem Kind die Puppe aus dem Wasser.

or

Er holte die Puppe des Kindes aus dem Wasser.

Answer 2

Structure-wise "erfüllen" has the same prototype as "geben". It is a transfer of object X (accusative) to receiver Y (dative)

Ich gebe dir(y) etwas (x)

"Erfüllen" is special in so far as only a very narrow semantic segment makes sense as X... wishes.

Ich erfülle dir (y) einen Wunsch (x).

The mere idea it could be one of the colloquial genitives is very very very very far fetched. As for the pronoun game... the context and the semantics of "erfüllen" makes it unclear that it's the kids' wishes, not the fary's. I cannot fulfill my wishes to you.

Answer 3

Edit: as noted by @Loong, it's likely just a plain dative + accusative, only formulated in a way that gives the impression of a "his genitive" instead. So what follows is to be taken with caution.

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I think it's a case of "his genitive" in which the questionable/dialectal dative + possessive form

... den Kindern ihre Wünsche

replaces the more correct

... die Wünsche der Kinder

Other examples:

*Der Frau ihr Auto (correct: Das Auto der Frau)

*Dem Kind seine Tasche (correct: Die Tasche des Kindes)

and even the title of the famous book

*Der Dativ ist dem Genitiv sein Tod (correct: Der Dativ ist der Tod des Genitivs)

where many incorrect uses of the german language are described and commented.

Native speakers will surely correct me if I'm wrong.