What is the advice for a couple, one of whom is a Muslim husband who abandons prayer and commits forbidden acts, and the other a Christian wife who wished to convert to Islam but was disheartened by her husband's actions, along with a clarification of the ruling on abandoning prayer according to scholars?

The scholars have agreed that one who abandons prayer, denying its obligatory nature, is a disbeliever (kafir). However, they differed on the ruling concerning one who abandons it due to laziness. The majority of them held that he should be asked to repent, and if he refuses, he should be executed as a legal punishment (hadd). Others held that he should be disciplined (ta'zeer) and imprisoned. The preponderant opinion is that one who abandons prayer is a disbeliever, even if it is due to laziness. This is the view of the general body of the Companions and imams such as Imam Ahmad. This difference of opinion entails many jurisprudential rulings related to inheritance, marriage, and other matters. As for the woman, if she embraced Islam, it is not permissible for her to remain with one who abandons prayer. If she is not Muslim, there are no Sharia rulings concerning her marriage to him. The wife is advised to leave this man and seek a true Muslim husband.