Is it permissible for a grandmother—who has married sons and daughters—to live alone in her house after her husband's death and to seek the help of a strange young man to stay with her overnight? And who are her mahrams with whom she is permitted to stay?

A person should not live alone due to the prohibition stated regarding it. The minimum status of this prohibition is that it is disliked (makrooh), and this is further emphasized if the person living alone is a woman. As for a grandmother hiring a young man to live with her, this is forbidden due to the unlawful seclusion (khalwa) involved. The maharim (unmarriageable kin) of a woman with whom seclusion is permissible are those who are permanently forbidden for her to marry.