Does a divorce take effect on a stepdaughter if the father says: "She will be divorced, and I will divorce," in the context of his discussion about his son's wife seeking a divorce, with the strong presumption that he intends it?

Uttering the words of divorce without the intention of effecting it does not result in divorce, because intention is an essential pillar of it. Thus, if someone narrates a past divorce, or commands it, or forbids it, his divorce does not take place due to his lack of intention to create it. Based on this, the father's conversation with his son about divorcing the son's wife does not effect a divorce upon the father's wife. It is advised to be wary of obsessive whispers (waswasa).