Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him)
Some of my relatives say offensive things about Allah and His Messenger. How should I deal with this?
If they will accept it, then give them sincere advice. If they will not accept it, and it is not absolutely necessary for you to be with them when they are saying these things, then avoid such gatherings. When you find the opportunity and people are ready to listen, speak to them about the greatness of Allah and His Messenger using rational proofs and firm evidence from the Qur’an and Sunnah.