Is it wrong to say that a man who does not impose hijab and prayer upon his daughters is not a complete believer, considering the noble Hadith: "Each of you is a shepherd and each of you is responsible for his flock," and is there sin in this because the father approves of their immodesty, abandonment of prayer, and listening to music?

Mutual advice among Muslims is a religious obligation, but it must be given with wisdom and gentleness. A father is responsible for raising his children, and care should be taken to increase his faith, not to judge it as deficient. Describing a father as having deficient faith may provoke his anger and lead to an accusation of falsehood, for the phrase "O disbeliever" would apply to one of them. The hijab (definition) is not one of the five pillars of Islam, but it is among the most emphasized obligations. The questioner should reconcile differences and explain that faith increases and decreases, and that he did not intend to declare his father a disbeliever but merely to advise him.