This is the 9511th most frequent German word.
mitschülern
"Mitschülern" is not a standard German word; it may stem from "Mitschüler," meaning "classmates."
Here, 'Mitschülern' refers to classmates in a dative case, whom the subject is assisting.
Ich helfe meinen Mitschülern bei den Hausaufgaben.
I help my classmates with their homework.
In this sentence, 'Mitschülern' refers to classmates belonging to the subject's brother, used possessively.
Die Mitschülern meines Bruders sind sehr freundlich.
The classmates of my brother are very friendly.
This use of 'Mitschülern' highlights its relational role concerning the subject, used in an instrumental context for the action of discussing.