Is it permissible for nieces to sit with their paternal uncle when he jokes with obscene words?

The questioner : This is a questioner from Riyadh who says: A man has his brother's daughters, and he jokes with obscene jokes. Is it permissible for them to sit with him? I ask the Honorable Shaykh to answer this question.

The Shaykh : The brother's daughters, meaning that their father's brother is their paternal uncle.

The presenter : Yes.

The Shaykh : He is a mahram (a relative one may not marry) to them without doubt, but if he speaks words that are vulgar and indicate lust, or looks with glances that indicate lust, then it is not permissible for them to uncover their faces in front of him, nor for any one of them to be alone with him. This is because fitnah (trial, discord or temptation) is very close in such a situation, and the basis for the obligation of hijab (the covering prescribed for women) is the fear of fitnah.