Is it permissible for a woman to travel without a mahram, even if she is with relatives?

The questioner : All right, Shaykh, there is a question about a woman who wants to travel with her husband's relatives to her hometown because she has not seen her parents for about two years. She will be traveling by car, and the trip may take two days. Of course, she will be in the company of women and trustworthy people, meaning the same people who are traveling. Is that permissible?

The Shaykh : His statement is haram (forbidden).

The questioner : No, she does not have a mahram; her mahram is tied up with work.

The Shaykh : Listen to my words. Answer me: only with a mahram.

The questioner : Without one, it is haram (forbidden).

The Shaykh : Only with a mahram. Yes, it is not permissible, even if they are relatives, I mean.

The questioner : Never, even if they are relatives, even if her mother is on her deathbed.