Is it permissible for me to tell my son that Al-Tahir Al-Haddad is a transgressor because he prohibited the implementation of God's law, based on verse 67 of Surat At-Tawbah, and was my son correct in declaring him an unbeliever?

The book "Our Woman in Sharia and Society" by the aforementioned author goes beyond the issue of hijab to daringly challenge established Islamic principles and advocate for emulating Western life, such as encouraging women to emulate European women in sports, demanding civil divorce, and rejecting polygyny, describing it as a bad Sunnah. This book led to a major campaign by Islamic scholars, and its author was stripped of his degree and expelled from his studies. A ruling of apostasy was issued against him by a scholarly committee headed by Sheikh al-Islam al-Maliki of Tunisia, Tahir ibn Ashour. Among the most prominent scholarly responses to it is the book "Mourning for the Woman of Mourning" by Sheikh Muhammad al-Salih ibn Murad.