he's not allowed to hep with the tests. its part of all the cores programming. Glados isn't allowed to help either but there are no levers in that test chamber so what she said had only one perpose, to make wheatley say the solution to the puzzle.
Let me tell you right now: This is my favorite thing on the internet. I love the animation, the way it all flows and just spot on character animation (and by that, I mean their movements are very in-character). Amazing work.