She left her husband’s house during the mourning period and went and stayed at her daughter’s house for two weeks
Question

                I am a woman who is observing the mourning period (following the husband’s death) and I have been staying in the house of my daughter, who has just had a baby, for more than two weeks now. What should I do?.
Praise be to Allah.
      You have to go back to your husband’s house straightaway 
      and stay there. This is a duty that you owe to your husband. 
Al-Tirmidhi narrated from 
    al-Furay’ah bint Maalik ibn Sinaan, who is the sister of Abu Sa’eed 
    al-Khudri, that she came to the Messenger of Allaah  (peace and 
    blessings of Allaah be upon him) and asked him about going back to her 
    people of Banu Khudrah, because her husband had gone out in pursuit of some 
    slaves of his who had run away, and when they were at the edge of al-Qadoom 
    he caught up with them and they killed him. She asked the Messenger of 
    Allaah  (peace and blessings of Allaah be upon him) to let her go back 
    to her family, because her husband had not left her with a house that he 
    owned or with any provision. The Messenger of Allaah  (peace and 
    blessings of Allaah be upon him) said: “Yes.” She said: So I left, and when 
    I was still in the mosque, he called me back or ordered that I be called 
    back, and said: “What did you say?” I repeated what I had told him about my 
    husband and he said: “Stay in your house until the appointed time.” She 
    said: So I observed my ‘iddah there for four months and ten days. When 
    ‘Uthmaan ibn ‘Affaan was the caliph, he sent for me and asked me about that, 
    and I told him and he followed what I said and ruled accordingly. 

    Classed as saheeh by al-Albaani in Saheeh Abi Dawood. 

    You also have to repent and pray for forgiveness for your 
    shortcoming.