Praise be to Allah.
The imams are agreed that it is not permissible for a woman whose husband has died to travel for Hajj during the ‘iddah period (mourning).
Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) was asked about a woman who resolved to go for Hajj with her husband, but her husband died in Sha’baan – is it permissible for her to go for Hajj?
She cannot travel for Hajj during the ‘iddah following her husband’s death, according to the view of the four Imams. End quote.
Majmoo’ al-Fataawa (34/29).
Shaykh Muhammad ibn Ibraaheem (may Allaah have mercy on him) said:
A woman who is in mourning cannot travel for Hajj, as is the view of the four Imams. With regard to what you say about only have leave during that time, this is not a shar’i justification that makes it permissible to travel with a woman who is still in the mourning period. End quote.
Fataawa al-Mar’ah al-Muslimah (2/899, 900).
And Allaah knows best.