What is the ruling on a wife remaining with her husband who deals in drugs and spends on her and their son from this unlawful money, and is it permissible for her to take her son and separate from him?

If all of the husband's money is unlawful, then it is not permissible to partake of it except out of necessity and to the extent of need. If it is mixed (lawful and unlawful), then it is permissible, though disliked. The wife must advise her husband, and if he insists on the unlawful, she has the right to seek divorce. It is not permissible for the wife to leave the marital home without her husband's permission, except out of necessity.