Using "de" in rappeler quelque chose/quelqu'un a' quelqu'un

Question

Why is "de" used in this example:Noël rappelle toujours de bons souvenirs à ma mère.Christmas always reminds my mother of good memories.but not in this example:Ça rappelle son enfance à mon frère.It reminds my brother of his childhoodThanks

Maarten Kamp · Accepted Answer

Susan, 
that is the partitive/indefinite article ‘ de ‘. 
It is not a verb -preposition expression - it is not ‘ rappeler à qqn de faire qqc ‘
This is also not the same as the reflexive verb-preposition expression ‘ se rappeler (de) ‘, as that conveys a different meaning. 
The English is ‘ ( some ) good memories ‘. The word ‘ some ‘ can be dropped in English, but the article cannot be dropped in French, and because it is in front of an adjective-noun expression in plural form, ‘ des ‘ becomes ‘ de ‘.  Hence ‘ de bons souvenirs ‘. 
In your other example, the article is not needed because of the possessive adjective ‘ son ‘ in ‘ son enfance ‘.
 https://progress.lawlessfrench.com/revision/grammar/expressions-for-remembering-se-souvenir-de-se-rappeler-de
 https://progress.lawlessfrench.com/revision/grammar/des-becomes-de-d-in-front-of-adjectives-preceding-nouns-french-articles
 https://progress.lawlessfrench.com/revision/grammar/use-mon-ma-mes-ton-ta-tes-son-sa-ses-to-say-my-your-his-her-possessive-adjectives