Is the situation in which a father treats his son's wife with flirtation, offers help, goes out with her alone, fulfills her requests, and stays with her at home during his son's absence considered normal, especially with her adorning herself, wearing perfume, dressing in tight clothes, not wearing a hijab, and discussing her private marital affairs with him, and is it permissible for them to remain alone in the house under these circumstances?

If the son suspects his father's interaction with his brother's wife, [regarding her] wearing tight clothes or going out without hijab, this is a great evil and a corruption of the father's fitra, as he should be the protector of his son's honor. The Prophet, peace and blessings be upon him, said: "If you have no shame, then do as you please," and this is a severe rebuke to one whom nothing deters from forbidden acts. They should be advised gently and kindly. If they do not stop, they can be threatened with informing the husband. If they still do not desist, then it is obligatory to inform him.