Status of Maternal Aunt in Islam

Can a disbeliever be regarded as a mahram for his Muslim sister when travelling?

Is the son of a half-sister regarded as a mahram?

The sister of the wife’s grandfather and the sister of her grandmother are forbidden for the husband in marriage as her paternal and maternal aunt are forbidden for him

Is my father a mahram to the wife of my half-brother through my mother?

The maternal and paternal uncles of the husband are not mahrams to the wife

The ruling on castration

The father’s (ex-)wife is a mahram to his sons even if she did not bear him any children

The husband’s grandfather is one of his wife’s mahrams

A woman’s maternal uncle and paternal uncle are mahrams to her and her daughters