All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, is His slave and Messenger.
The ‘Manhaj of the Salaf’ (methodology of the righteous predecessors) is the correct Manhaj for a very simple and self-evident reason, namely, that the Salaf are the ones who received the knowledge of the Quran and Sunnah directly from the Prophet . Therefore, they had the best and most perfect understanding of the divine revelation conveyed to them by the Prophet because it was revealed in their own language and he lived amongst them (and this was a practical example). Moreover, Allah, The Exalted, praised them, their understanding, knowledge and deeds in many occasions in the Quran; He Says (what means): {And the first forerunners [in the faith] among the Muhaajireen and the Ansaar and those who followed them with good conduct – Allah is pleased with them and they are pleased with Him…} [Quran 9:100] There are many verses to the same effect. Also, it was authentically narrated on the authority of ‘Imran ibn Husayn, may Allaah be pleased with him, that the Prophet said: “The best among people are my generation, then those who follow them, and then those who follow them.” Hence, the texts of the Quran and Sunnah as well as the sound intellect testify to the fact that their methodology was the soundest, their practices were the most guided, and their righteous path was the best. Knowing that, you should clarify it to your father and those around you with kindness, gentleness, wisdom, and good instruction. If they responded to you, then all praise be to Allah; otherwise, you should not despair of clarifying the matter to them and patiently calling them to the right path. You should also be a good example for them to prove to them the truth of what you are preaching and urging them to do. May Allah bless you with all that is good.
Allah Knows best.