What is the ruling on a woman in 'iddah traveling to stay overnight in university housing for an exam, given the presence of her adult son?

The basic principle is that a woman observing the 'iddah (waiting period) after her husband's death should not spend the night outside her home, nor should she leave it except out of necessity. She is permitted to go out during the day to buy food or yarn, and at night to a neighbor's house for spinning yarn and conversation, provided she returns and spends the night in her own home. If the student is the woman observing the 'iddah, and she cannot postpone her studies, and is compelled to stay in university housing due to its distance and fear of hardship, then she is permitted to do so. However, if it is her son who is studying and he can manage without her, then she is not permitted to spend the night outside her residence.