Praise be to Allaah.
The woman who is in ‘iddah following the death of her husband
has to stay in her marital home until her ‘iddah ends.
It was narrated from Abu Sa‘eed al-Khudri (may Allah be
pleased with him) that the Prophet (blessings and peace of Allah be upon
him) said to his sister al-Furay‘ah bint Maalik (may Allah be pleased with
her): “Stay in the house in which the news of your husband’s death came to
you, until your ‘iddah is over.”
Narrated by al-Tirmidhi, 1204; Abu Dawood, 2300; al-Nasaa’i,
200; Ibn Maajah, 2031. Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
It is permissible for her to go out of her house during the
day for necessary purposes, such as to go to the market and buy what she
needs, or to go to work, and so on.
But at night she should not go out except in the case of
necessity, such as if thieves attack her house and the like.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him)
said:
The woman who is in ‘iddah following the death of her husband
has to wait for four months and ten days, and she should avoid adornments
and perfume on her body and clothing; she should not wear adornments or put
on perfume or wear fancy clothes. She should stay in her house and not go
out during the day unless it is for a need, and she should not go out at
night except in the case of necessity.
It is permissible for her to do everything that is
permissible in times other than ‘iddah, such as speaking to any man she
needs to speak to if she is properly covered, and so on.
What I have mentioned is the Sunnah of the Messenger of Allah
(blessings and peace of Allah be upon him) which was the practice of the
women of the Sahaabah when their husbands died, and it was the practice of
the wives of the Prophet (blessings and peace of Allah be upon him) too.
Majmoo‘ al-Fataawa, 34/27, 28
It is not permissible for her to go out of her house for the
purpose of receiving condolences, as mentioned in the question, because if
it is not permissible for her to go out for Hajj during the ‘iddah period,
it is more appropriate that she should not go out to the house of her
husband’s father in order to receive condolences.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him)
was asked about a woman who intended to go for Hajj with her husband, then
her husband died in Sha‘baan. Is it permissible for her to go for Hajj?
He replied:
She does not have the right to travel for Hajj during the
‘iddah following her husband's death according to the opinion of the four
imams.
Majmoo‘ al-Fataawa, 34/29
For more information please see the answer to question no.
72269
The basic principle is that those who wish to offer
condolences should go to the bereaved household to offer condolences, and
the bereaved should not go to another house in order to receive
condolences.
And Allah knows best.