To what extent is what the husband does, in terms of habits that violate Sharia and the wife's traditions, forbidden and grievous, and what is the solution to these problems, knowing that the husband is aware of his wife's opposition to these habits?

What the husband does by being lenient in dealing with non-mahram (definition) women is a reprehensible and forbidden act. It is not permissible to obey him in shaking hands with non-mahram men, just as it is not permissible to delay prayer beyond its time without a valid excuse. Looking at pictures of immodestly dressed women (al-kasiyat al-ariyat) is forbidden. The wife must advise her husband gently and wisely, inform him of the words of scholars clarifying the limits of the Sharia (definition), encourage him to attend scholarly gatherings, associate with righteous people, and cooperate with him in acts of obedience, while being careful not to use harsh words or engage in excessive argumentation. She should seek Allah's help, be a good wife to her husband, and supplicate for him.