Teaching a Mother her Religious Duties is a Part of Being Dutiful to Her
Question :
Since my father died, my mother has lived with us. She is illiterate and is incapable of memorizing even short chapters of the Qur'an. Nonetheless, she performs her obligatory and voluntary worship (prayer and fasting) assiduously. What is the best way to be dutiful to her so that we may achieve Allâh's pleasure?
Answer:
It is incumbent upon you to be dutiful to her in religious as well as customary matters. In religious matters, you should teach her what is obligatory upon her in terms of worship, in deeds of speech and of action, being gentle and patient with her in any of her shortcomings. If she becomes angry and speaks harsh words with you, you must be patient. And remember, completeness in anyone can only come after a long period of patience and perseverance.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 7 Pages 307-308