The ruling on praying behind a sleeping person and their movement in front of the one praying

Question:
Is there evidence for the prohibition of praying behind a sleeping person?

Answer:
No, there is no harm in that.
Q: The movement, while he is sleeping?
The Shaykh: It does not harm.
Q: What counts as passing by?
The Shaykh: It does not count as passing by.
Q: Her slipping out from in front of the Messenger of Allah (peace and blessings be upon him), is that not passing by?
The Shaykh: Her slipping out is not passing by; she slips out from the bed, slipping out from the side of her head.
Q: You say: So I slip out from near his feet?
The Shaykh: Whether from near his feet or from near his head, it is all the same; it is not called passing by. Passing by is coming from one side to the other.
Q: In some hadiths, Aisha (may Allah be pleased with her) was on the bed, would not the entire bed be...?
The Shaykh: She was on top of the bed, and the Prophet (peace and blessings be upon him), when he prostrated, would nudge her feet so that she would hold her feet still, while she was sleeping.