All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If a woman travels for Hajj and then she gets to know that her husband died, then if she had already assumed the state of Ihraam, she is obliged to continue the Hajj and then return after Hajj and complete her waiting period at her home. Similarly, if he died while she was on her journey, it is permissible for her to continue her Hajj.
Shaikh Ibn ‘Uthaymeen was asked: “A woman intended to fulfil the obligation of Hajj and she had paid for the airline ticket and then her husband died, is it permissible for her to go for Hajj while in her waiting period?” He answered: “It is not permissible for her to go to Hajj during her waiting period; rather, she is obliged to stay at her dwelling home where her husband died and then go to Hajj the next year. However, if he died while she is on her way, then it is permissible for her to go on her journey and continue her Hajj and then go back to her country soon after the completion of Hajj so that she would observe her waiting period in her home.”
Allaah Knows best.