What should we do about our father who does not fast Ramadan, and drinks tea and smokes in front of us while we are fasting, and refuses our advice? And are we partners with him in sin? And is it permissible for us to eat from his food in Ramadan?

Whoever intentionally breaks their fast in Ramadan (definition) commits a grave sin, and they must repent and make up for it. As for you, you must advise him with wisdom, good admonition, and high etiquette, without harshness, while supplicating for him and being patient, as Allah Almighty says: "And enjoin what is right and forbid what is wrong and be patient over what befalls you. Indeed, that is [from] the matters [requiring] determination." If you advise him, you have absolved yourselves; "So remind, [for] you are only a reminder. You are not over them a controller." And eating from his food is permissible as long as his money is lawful.