My nephew was sued, what should I do?

He joined a presidential fan cafe just to mess around and cause trouble,
and ended up getting into an argument with a woman. In a fit of anger,
he took a photo of his genitals, found her Instagram account,
and sent it to her.
She reported him for sexual harassment, and now the police
have called him. The thing is, he is only in 5th grade.
Will the punishment be severe?