What is the ruling on insulting the children and fathers of prophets? Such as the son of Prophet Noah.

It is advisable to avoid overly detailed questioning about matters that have no practical consequences, such as your question about the son of Noah or the father of Abraham. The early Muslims (Salaf) disliked this type of questioning.

Regarding the ruling on reviling the dead, it has been narrated from the Prophet, peace be upon him, who said: "Do not revile the dead, for they have gone on to what they have sent forth." Some commentators understood this prohibition as general, while others qualified it, permitting reviling for a legitimate Sharia interest, or if no living Muslim is harmed by it.

The prohibition of reviling these specific deceased individuals is emphasized for several reasons: the generality of the prohibition against reviling the dead, the absence of any benefit in doing so, and because reviling the son of a prophet or his father constitutes an insult to the esteemed position of the prophets themselves.