Kindness to parents is placed by Allah directly after His own worship, and He forbids even a word of impatience toward them, especially in their old age (Qur'an 17:23-24). When a man asked the Prophet (ﷺ) who was most deserving of his good companionship, he answered 'Your mother' three times before saying 'Your father,' showing the mother's heightened right. This duty of birr remains binding even if the parents are disbelievers or sinful, though obedience stops where it would mean disobeying Allah.
Evidence — the daleel
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.