How can one correct the ideas of a colleague who professes the Shia doctrine and loves the Messenger, may Allah bless him and grant him peace, considering that he is 15 years old and his family may be likewise, and what are some small and convincing books that can be gifted to him?

The person striving to guide their colleague is advised to possess good character and kind treatment, so that their colleague trusts them and accepts their advice. The caller to Islam must have sufficient knowledge of the reality of the false doctrine their colleague adheres to, and of the doctrine of the Ahl al-Sunnah, and the differences between them, by reading concise books such as: "The Broad Outlines of the Foundations Upon Which the Religion of the Shi'a Was Built," and "Questions That Led Shi'a Youth to the Truth," in addition to the book "Scientific and Practical Means for Calling the Shi'a." After understanding, one can begin to discuss important issues with them, such as Tawhid (monotheism), the belief concerning the Qur'an, and the Companions, or begin with the virtues of the Companions from the Holy Qur'an if time is limited and their colleague is receptive.