What is the ruling on these actions and beliefs prevalent among the people of this friend, and how can he advise them while maintaining kinship ties?

Contemporary Sufi groups exhibit doctrinal deviations and opposition to guidance. Polytheistic practices are prevalent among them, such as invoking others besides Allah, seeking their aid, and believing that those they call 'saints' can bring benefit or harm. This resembles the polytheism of the early idolaters who took idols as intermediaries to bring them closer to Allah. The داعية (caller to Islam) should invite his relatives with wisdom, gentleness, and patience, breaking the barrier of fear, emulating the Messenger of Allah, peace and blessings be upon him. If they do not respond, it is obligatory to abandon them in their innovations and in places related to them, while still permitting eating with them to maintain kinship ties.