What is the reason for the abundance of problems at home despite my diligence in prayer, fasting, and supplicating for my father and siblings' guidance, even though they do not pray?

We advise you to supplicate for your family's well-being and to enjoin them to good and forbid them from evil with gentleness, especially regarding their abandonment of prayer. You can use indirect methods such as letting them hear lectures and sermons, and by being a good role model for them in your character and patience. Familial problems may be due to sins, as Allah Almighty said: "And whatever strikes you of disaster - it is for what your hands have earned; but He pardons much." Perhaps their repentance and turning back to Allah will mend the situation and remove the problems.