How can one deal with a mother's and sisters' repeated refusal to discuss religious matters considered erroneous in the Sunni school of thought, such as prostrating on a turbah, listening to distorted adhan, not wearing the hijab, and traveling without a mahram, as well as their criticism of watching Islamic channels and following Sunni fatwas, while maintaining kinship ties and avoiding قطع الرحم (severing ties)?

Congratulations on your repentance. You should continue to guide your family, acting upon the verse: "O you who have believed, protect yourselves and your families from a Fire," using permissible means, wisdom, gentleness, and kindness towards them. Kindness to one's mother is obligatory unless she commands disobedience. Be sure to provide them with a daily dose of faith, and acquire useful resources and tapes for them, under the pretext of strengthening their Arabic language. Seek help through prayer, and focus on issues of faith in Allah, the Quran, the Prophet, the Companions, the angels, and the Afterlife. Read books that clarify the truth regarding these matters.