Praise be to Allah.
This question involves two issues:
1 – A woman seeing her husband’s body after his death
2 – A woman seeing her mahrams.
1 – It is permissible for a woman to see her husband’s body, and there is no reason why she should not. Indeed, a wife has the right to wash her dead husband. Imaam Maalik narrated in al-Muwatta’ from ‘Abd-Allaah ibn Abi Bakr that Asmaa’ bint ‘Umays washed Abu Bakr al-Siddeeq when he died, then she went out and asked the Muhaajireen who were present, “I am fasting and the day is very cold; do I have to do ghusl?” and they said, “No.” (al-Janaa’iz, 466). The author of al-Muntaqa ‘ala Sharh al-Muwatta’ said concerning this hadeeth: this indicates that it is permissible for a woman to wash her husband after he has died, because this happened in the presence of a number of the Sahaabah, especially since Abu Bakr had left instructions in his will to that effect. No difference of opinion is known of among the Sahaabah concerning this matter, which indicates that there was consensus.
It was narrated that ‘Aa’ishah said, “If I could go back and change anything, nobody would have washed the Messenger of Allaah (peace and blessings of Allaah be upon him) except his wives. ” (narrated by Ibn Maajah, al-Janaa’iz, 1453; classed as saheeh by al-Albaani in Saheeh Ibn Maajah, no. 1196). If a woman is permitted to wash her husband;s body, then it is definitely permitted for her to see her husband’s body.
This ruling applies only if the woman is still within the ‘iddah period. If her ‘iddah period has ended, for example if she was pregnant but gave birth straight after her husband died, then it is not permissible for her to wash him or to see him.
I (Shaykh al-Munajjid) asked Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) before he died about a man who dies and his wife gives birth a few hours later – can she wash her husband?
He replied: No, because when she gives birth the connection between her and her husband is severed, so it is not permissible for her to wash him, because he is now no longer her husband.
Mi’ah Faa’idah min al-‘Allaamah al-Shaykh Ibn ‘Uthaymeen (tape).
What is forbidden is for women to wail over the deceased. It was narrated in a hadeeth that Umm ‘Atiyah (may Allaah be pleased with her) said: “The Prophet (peace and blessings of Allaah be upon him) took our pledge of allegiance to him on the grounds that we would not wail (over the dead). None of us fulfilled their promise except five women: Umm Sulaym, Umm al-‘Alaa’, the daughter of Abu Sabrah the wife of Mu’aadh and two other women, or the daughter of Abu Sabrah, the wife of Mu’aadh and one other woman.” (Narrated by al-Bukhaari (al-Janaa’iz, 1223).
It was narrated from Abu Maalik al-Ash’ari that the Prophet (peace and blessings of Allaah be upon him) said: “There are four things in my ummah from the jaahiliyyah which they will not give up: pride in one’s ancestry, slandering the lineage of others, seeking rain from the stars and wailing over the dead. If the woman who wails does not repent before she dies, she will be raised on the Day of Resurrection wearing a garment of tar and a shirt of scabs.’ (Narrated by Muslim, al-Janaa’iz, 1550).
2 – It is permissible for a woman to see her mahrams, and she does not have to observe hijaab in front of them.
There is no connection between the death of a woman’s husband and her seeing her mahrams. Hence it is recommended for her mahrams to offer condolences to her, by them seeing her, shaking hands with her, sitting with her and talking to her. No dispute is known among the scholars concerning this.
Al-Nawawi (may Allaah have mercy on him) said: al-Shaafa’i and his companions said: it is recommended for all the relatives of the deceased to offer condolences to his wife, old and young, men and women, unless the wife is young, in which case only her mahrams should offer condolences.
What the questioner describes is nothing more than the myths and ignorance of the common people.
Shaykh Muhammad ibn Ibraaheem (may Allaah have mercy on him) was asked about a woman covering her face in front of her mahrams. He said:
That is not permissible, because it is not part of Islam, rather that is the myths and ignorance of the common people.
See al-Faatawa al-Jaami’ah li’l-Mar’ah al-Muslimah, part 2, p. 709, And Allaah knows best.