Al-Mawdudy's view regarding observing Hijab in the presence of the husband's relatives

Q 3: His Eminence Shaykh Abu Al-A`la Al-Mawdudy in his book Tafsir Surah Al-Nur, commenting on Allah's saying: And tell the believing women to lower their gaze (from looking at forbidden things) stated: "Relatives who are not eternally forbidden to marry a woman shall not be regarded as complete Mahram (spouse or permanently unmarriageable relative) relatives, and are therefore not allowed to see the woman unveiled. They shall also not be regarded as complete non-Mahram that they may not see the woman unless completely veiled. Thus, how should such a woman behave toward them between these two extremes? In fact, this is not provided for by Shari`ah (Islamic law), as it is not possible... Etc." To what extent is such an opinion, that it is not possible for Shari`ah to provide for, right?

A: Allah (Exalted be He) defined Mahram relatives as well as other men to whom a woman can show her adornment in the following Ayahs (Qur'anic verses): Tell the believing men to lower their gaze (from looking at forbidden things), and protect their private parts (from illegal sexual acts). That is purer for them. Verily, Allâh is All-Aware of what they do. And tell the believing women to lower their gaze (from looking at forbidden things), and protect their private parts (from illegal sexual acts) and not to show off their adornment except only that which is apparent (like both eyes for necessity to see the way, or outer palms of hands or one eye or dress like veil, gloves, head-cover, apron, etc.), and to draw their veils all over Juyûbihinna (i.e. their bodies, faces, necks and bosoms) and not to reveal their adornment except to their husbands, or their fathers, or their husband’s fathers, or their sons, or their husband’s sons, or their brothers or their brother’s sons, or their sister’s sons, or their (Muslim) women (i.e. their sisters in Islâm), or the (female) slaves whom their right hands possess, or old male servants who lack vigour, or small children who have no sense of feminine sex. (Part No. 17; Page No. 207) In fact, Allah did not include one's wife's sister, paternal or maternal aunt under this category. Undoubtedly, your Lord is never forgetful. Accordingly, the categories of women mentioned above are Ajanib (women lawful for the man to marry) for a sister's husband, a brother's daughter's husband and a sister's daughter's husband. Moreover, they are not in a middle position between Mahrams and Ajanib. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.