What is the ruling on dealing with relatives who commit major sins such as cursing the Lord and abandoning prayer? Is it obligatory to avoid congratulating them on occasions? What is the ruling on attending mixed gatherings that are not free of reprehensible acts such as backbiting and smoking shisha? Am I sinful for accompanying immodest women out of necessity?

If your paternal uncles and their sons abandon prayer and curse the Lord, they are in grave danger. Abandoning prayer is a major sin, and cursing the Lord is disbelief by the consensus of scholars. Anger is not a deterrent to accountability unless it causes loss of consciousness. You must supplicate for their guidance, enjoin good, and forbid evil to the best of your ability. The least of this is to disapprove with your heart and leave the place of evil. It is permissible to sit with your father while watching television as long as there is nothing forbidden in it, and the same applies to gatherings of backbiting. Shaking hands with your paternal uncles' sons is forbidden. As for your paternal uncles, they are maharim (unmarriageable kin), and it is permissible to shake hands with them and unveil in their presence. Difference in religion does not prevent mahramiyyah (being unmarriageable kin), but if there is any suspicion from one of them, he should be treated as a stranger. It is not advisable to stop congratulating family members to avoid animosity. Family gatherings are permissible with Islamic controls, but if there is leniency in them, such as immodest display or jesting with non-mahram individuals, then it is not permissible to sit with them.