Is it permissible for a woman observing her 'iddah to stay in her daughter's house if her daughter's husband's adult son is also in the house?

If the daughter's husband's son is a stranger to the woman observing 'iddah, then it is not permissible for her to reside with him in the same house unless the Sharia-compliant regulations are met. These regulations include the woman observing 'iddah having her own room with an independent entrance and exit, and independent facilities (such as a bathroom and kitchen). The woman observing 'iddah must remain in her deceased husband's house until she completes her 'iddah, and it is not permissible for her to change residences except out of necessity.