My older sister is advanced in age and has a weakness in her mental development, and my mother orders her to pray. Is that valid?

Question:
The Honorable Shaykh, may Allah grant you success, says: The questioner says to me, "My older sister is a minor in her intellect and has a medical report." He says to me, "My older sister is a minor in her intellect."

Answer:
The wage. Yes, she is a minor in her intellect. Yes. And she has a medical report regarding a weakness in her mental development. He says, "And my mother, after the father passed away, obtained a guardianship document for her, and she orders her to pray and fast, even though this girl does not know the days, not Saturday from Sunday. What is the ruling on ordering her to do these things?" If she knows what she is told, then she is ordered to do it. If she does not know what she is told, then she is not ordered to do it.