Is it permissible to pray for this woman to be distanced from her husband so that her situation may improve, and is it permissible to pray to marry her?

A man's disbelief by reviling Allah or the religion, or by abandoning prayer, invalidates the marriage (nikah), and the schools of thought among the jurists differ on this matter. Therefore, the wife should strive to free herself from this husband by seeking divorce. There is no harm in a woman supplicating to be rid of her husband if he does not repent, and there is no harm in asking Allah to marry her after she is free from him, provided it is for good. However, asking Allah to marry a woman who is already married to a Muslim is an transgression in supplication and a forbidden envy.