YOU SAID:
his apprentice killed him in his sleep
INTO JAPANESE
彼の弟子は彼の睡眠で彼を殺した
BACK INTO ENGLISH
His disciples killed him in his sleep
INTO JAPANESE
彼の弟子は彼の睡眠で彼を殺した
BACK INTO ENGLISH
His disciples killed him in his sleep
That didn't even make that much sense in English.