Are the wife's relations by fosterage (her husband, his brothers, his sisters, her brothers, her sisters) considered her husband's mahram?

The general rule is that fosterage prohibits what lineage prohibits. Thus, the husband of the foster mother, from whom the milk originated, is considered a father to the infant girl through fosterage, and his brothers are her paternal uncles, and his sisters are her paternal aunts. Likewise, the brothers and sisters of the foster mother are considered maternal uncles and aunts to the one she nursed.