Is it permissible for the husband's brother to take his brother's wife to the doctor when the husband is absent or apologizes?

It is not permissible for a wife to ride alone in a car with her husband's brother, due to the seclusion (khalwa) involved, which the Messenger of Allah, peace and blessings be upon him, warned against by saying: "Beware of entering upon women." They said: "O Messenger of Allah, what about the husband's brother (al-hamu)?" He said: "The husband's brother is death." Thus, it is not permissible for a man to be in seclusion with his brother's wife, whether in a car or at home. Similarly, it is not permissible for any woman to be in seclusion with a man who is a stranger to her, even if he is from her husband's relatives, her own relatives, or her neighbors, unless she is accompanied by a mahram. Also, it is not permissible for a woman to travel without a mahram, based on what was reported from the Prophet, peace and blessings be upon him: "No man should be in seclusion with a woman unless she has a mahram with her, and no woman should travel except with a mahram."