@raja90277,
I rather disagree that the issue is just between his parents. Not only is it affecting him, but the behaviour (seeing other women off in front of the house - presumably the wife suspects him of sleeping with them) is quite rude (in my view, it's quite despicable behaviour).
I'd have no issue calling out anyone that behaved like like towards a loved one of mine, even if he were my father.
The conversation of course, is about the rude behaviour, and not about the state of their relationship.
And of course, if the OP didn't mean that (that's what I think he means), then disregard