Indeed, Islam orders us to be kind and loyal to parents, whether or not they are Muslim. Referring to this, Allah Almighty says: “Thy Lord has decreed, that you worship none save Him, and (that you show) kindness to parents. If one of them or both of them attain old age with thee, say not ‘Fie’ unto them nor repulse them, but speak unto them a gracious word.” (Al-Isra’: 23)
However, favoring parents and being dutiful to them is not allowed if it involves disobedience to Allah.
Dr. Muzammil H. Siddiqi, former President of the Islamic Society of North America states: “This is an authentic Hadith and it is mentioned in many books of Hadith. In one version reported by Ibn Majah it is mentioned that the Prophet told a person, “Be at your mother’s feet and there is the Paradise.” (Ibn Majah, Sunan, Hadith no. 2771)
The meaning of the Hadith is that you should serve your mother and take good care of her. Obey her as long as she does not tell you to do something haram.
It does not make any difference whether the mother is Muslim or non-Muslim. It is the duty of the children to be respectful to their parents, especially mothers. Allah says in the Qur’an:
“And We have enjoined on man (to be good) to his parents: in travail upon travail did his mother bear him, and in years twain was his weaning: Show gratitude to Me and to thy parents: to Me is (your final) Goal. But if they strive to make thee join in worship with Me things of which you have no knowledge, obey them not; yet bear them company in this life with justice (And consideration), and follow the way of those who turn to Me. In the End the return of you all is to Me, and I will tell you the truth (and meaning) of all that you did.” (Luqman: 14-15)
If the mother is a pious Muslim woman, then she is the woman of Jannah (Paradise) and in her service indeed there is Jannah. But if she is not a pious Muslimah or if she is not a Muslimah, still your Jannah is in her service because you serve her in obedience to Allah. The Jannah of the children is near the feet of their mothers, but the Jannah of the mothers is in their own obedience to Allah.”
Excerpted, with slight modifications, from: