How can one deal with a husband who neglects his wife emotionally and financially, and mistreats her in front of his family, thereby threatening the stability of the family and affecting the upbringing of the children?

Among the wife's rights upon her husband are maintenance and clothing according to what is customary. If he withholds them or is stingy with them, then she may take from his wealth what suffices her and her child according to what is customary, without his knowledge. It is not permissible for the husband to neglect his wife; rather, he must give her her rights, treat her kindly, respect her feelings, and not humiliate her, even if he dislikes her, as Allah Almighty says: ﴿And live with them in kindness. For if you dislike them - perhaps you dislike a thing and Allah makes therein much good.﴾ [An-Nisa: 19]. The wife is advised to be patient, out of concern for the children, seeking reward, and hoping for the husband's guidance.