All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Scholars of the four schools of thought are agreed that a woman whose husband has passed away is required to observe her Iddah ( Waiting period that a Muslim woman observes after the death of her husband or after divorce ) in the house where she was living with her husband when she received the sad news of his passing away. This is regardless of whether the house is rented or owned by the husband. The evidence on this is that Allah the Almighty says {what means}: "…. and turn them not out of their houses, nor shall they (themselves) leave, except in case they are guilty of some open lewdness." {At-Talaq, 1}.
Another evidence is that Zaynab, daughter of Ka'b ibn Ujrah narrated that Furay'ah daughter of Malik ibn Sinan, told her that she came to the Messenger of Allah (Peace be upon him) and asked him whether she could return to her people, Banu Khidrah, for her husband went out seeking his slaves who ran away. When they met him at al-Qudum, they murdered him.
So I asked the Messenger of Allah (Peace be upon him):
"Should I return to my people, for he did not leave any dwelling house of his own and maintenance for me?
She said: The Messenger of Allah (Peace be upon him) replied: Yes. She said: I came out, and when I was in the apartment or in the mosque, he called for me, or he commanded (someone to call me) and, therefore, I was called.
He said: what did you say? So I repeated my story which I had already mentioned about my husband. Thereupon he said: Stay in your house till the term lapses. She said:
So I passed my waiting period in it (her house) for four months and ten days. When Uthman ibn Affan became caliph, he sent for me and asked me about that; so I informed him, and he followed it and decided cases accordingly." {Related by Abu Dawoud}.
Moreover, she is entitled to pay the rent of the house during the whole period of Iddah (Four months and ten days) from the husband`s estate. This is in adherence to the ruling of Sharia which states that she is required to stay in the house where she used to live with her late husband, as stated some scholars.
A woman whose husband has passed away is required to stay in the house where she was living with her husband when she received the sad news of his death, regardless of location of that house. She must also avoid travelling during her Iddah for she doesn`t have to do so…..Scholars have agreed that it is forbidden for her to travel during her Iddah. However, if her husband left no estate from which she can pay the rent, she felt insecure about being alone in that temporary residence or the effective laws of the country where she is ban her staying there for the whole period of Iddah, then she is allowed to return to her country, even if she had to travel for a long distance without a chaperone. For more details, check Moghni al-Mohtaj, V.5:107} by Al-Shirbini.
In conclusion, if the widow mentioned in the afore question was able to complete her Iddah in the flat that her husband rented in Turkey, didn`t feel insecure about being alone and the laws of that country didn`t object to her staying there, then she must remain there. Otherwise, she is allowed to return to her country to complete her Iddah in her husband`s house. And Allah the Almighty knows best.