They observe reciting Surah Al-Kahf on Fridays regularly

A 9: Reciting Surah Al-Kahf on Friday is a Mustahab (desirable) act, based on Hadiths related in this regard. The Prophet (peace be upon him) said: Whoever recites Surah Al-Kahf on Friday will have light that shines for them from that Friday until the next. (Related by Al-Nasa'y and Al-Hakim in his Sahih [authentic book of Hadith] through a good Isnad [chain of narrators]). With regard to what is mentioned in the question that (Part No. 7; Page No. 105) reciting Surahs (Qur'anic chapters) other than Surah Al-Kahf on Friday is insufficient, it is a baseless opinion.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.