The mother's conception of the transaction is equally limited and imperfect, though in a different way.

She thinks only that if she were to treat the child with kindness and sympathy, she would be taking the part of a bad boy against his teacher; whereas, in reality, she might do it in such a way as only to be taking the part of a suffering boy against his pain.
It would seem that the true and proper course for a mother to take with a child in such a case would be to soothe and calm his agitation, and to listen, if need be, to his account of the affair, without questioning or controverting it at all, however plainly she may see that, under the blinding and distorting influence of his excitement, he is misrepresenting the facts.

Let him tell his story.

Listen to it patiently to the end.

It is not necessary to express or even to form an opinion on the merits of it.
The ready and willing hearing of one side of a case does not commit the tribunal to a decision in favor of that side.