What level of knowledge and religiosity must a husband possess to be a shepherd for his family and responsible for his flock, and is he sinful if his wife or children commit something forbidden by Islamic law due to his failure to advise them beforehand?

A man is a guardian and responsible for the education and upbringing of his wife and children. If he falls short in this and causes them to fall into sin, he is blameworthy. If he is not falling short, then he must remind and admonish them after they commit violations of Islamic law. The education of children begins from the age of discernment, by teaching them religious upbringing, the Quran, hadiths, Islamic rulings, and supplications, and by forbidding them from lying and backbiting so that they become accustomed to good and abandon evil from a young age, because neglecting their upbringing leads to their deviation and corruption. Fathers are responsible for their children, and their neglect and shortcomings in guiding and raising them in matters of religion is a major mistake, and many fathers are preoccupied with worldly matters over their children.