Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
No Muslim with a conscience can doubt their duty to take care of their parents. By failing to do so, especially when they are helpless, they are depriving their chance to enter paradise.
Responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
Duty to parents in Islam
Honoring parents and serving them is one of the most critical teachings of the Quran. Furthermore, according to the Quran, it is an essential teaching of all the previous revelations.
Honoring parents and treating them with kindness is a pivotal commandment in Islam, second only to our duty to worship Allah.
Allah says, “Your Lord has commanded that you worship none but Him and that you be good to your parents. Therefore, if either of them or both of them reach old age with you, do not say a word of disrespect, nor scold them, but say kind words to them. And lower to them the wing of humility, out of mercy, and say, ‘My Lord, have mercy on them, as they raised me when I was a child.”‘ (Al-Baqarah 17: 23-24)
“Worship God, and ascribe no partners to Him, and be good to the parents, and the relatives, and the orphans, and the poor, and the neighbor next door, and the distant neighbor, and the close associate, and the traveler, and your servants. God does not love the arrogant showoff.” (An-Nisa 4: 36)
The Quran also tells us that it was also the commandment in all previous revelations, including Torah and Gospel:
“We made a covenant with the Children of Israel: ‘Worship none but God, and be good to parents, and relatives, and orphans, and the needy; and speak nicely to people, and pray regularly, and give alms.” (Al-Baqarah 2: 83)
Neglecting parents in Islam
If honoring and rendering acts of kindness to parents is the second of the foremost religious duties in Islam, neglecting one’s parents is one of the most heinous sins. Just as the shirk is the gravest of all sins in Islam, neglecting one’s parents is the second cardinal sin.
The Prophet (peace be upon him) has warned us against it in so many words. Once, he asked his companions, “Shall I tell you the three of the gravest sins?” Then he said, “It is to associate partners with Allah, displeasing one’s parents and bearing false testimony.” (Al-Bukhari)
In another tradition, we read, “They are the most disgraced ones: Those who could not enter paradise by ignoring to serve their old parents, either both of them or one of them.” (Muslim)
On another occasion, when a young man came to the Prophet (peace be upon him) asking permission for going for Jihad, the Prophet told him: “Go and take good care of your parents. That is the best Jihad you can perform.” (Al-Bukhari)
The Prophet knew that the man had come leaving old parents who needed his care behind him.
In light of these clear teachings of the Quran and Sunnah, no Muslim with a conscience can doubt their duty to take care of their parents. By failing to do so, especially when they are helpless, they are depriving their chance to enter paradise. That is the clear lesson that the Prophet (peace be upon him) has imparted to us in the above tradition.
Almighty Allah knows best.