The laws of rechilus apply to all Jews. There is no difference whether the speaker is a relative or stranger. And there is no difference whether the person being spoken about is an adult or a child.
Furthermore, a son or daughter who hears someone speak badly of his or her parent cannot relate this to the parent. For example, if a son hears a nasty comment about his father, he cannot tell his father about it. Though he is motivated by a desire to honor his father, he will honor him more by obeying the Torah’s command not to speak rechilus.
As we stated, it is forbidden to speak rechilus about a child. The Chofetz Chaim offers an example which shatters a common misconception:
Shimon’s son is fighting with Levi’s son in the park, and Shimon’s son has the upper hand. Reuven happens to be strolling through the park at that time. He is a good friend of Levi and he knows exactly what to do — at least, he thinks he does.
The next time Reuven meets Levi, he tells him how Shimon’s boy “was giving it” to his son. Levi is not pleased. The next time Levi sees Shimon’s son, he pulls him aside and tells him in no uncertain terms that if he ever goes near his son again he will regret it. To make it clear that “he means business,” Levi slaps the boy on both cheeks.
Shimon’s son now tells his father, who in turn is incensed at Levi. A full-scale feud erupts, and how did it all begin? With the rechilus reported by Reuven.
The Chofetz Chaim is not suggesting that we never inform a parent when his child is the victim of aggression. What he is telling us is that rechilus about children is also rechilus and therefore we need to fulfill all the conditions of toeles (constructive speech) before informing a father of such matters. In our example, Reuven must first ask himself: “Am I certain that my understanding of the incident is correct? Perhaps Levi’s son instigated the fight and teased the other boy until he felt the need to retaliate?
“What will I accomplish by telling Levi about the incident? And if there is something to accomplish, perhaps it could be done by speaking to Shimon about his son, so as to avoid speaking rechilus?” Other questions relating to the conditions of rechilus l’toeles (for a constructive purpose) need to be addressed as well.