Does he have money of his own? I agree that behavior is always a signal (or symptom, or communication of something.) Generally, sneaking behaviors indicate fear of some sort--even just a feeling of "this is the only way I can make sure I get what I need/want" or "I have to do this to make it happen." Lying, sneaking, and hiding all indicate fearfulness on the child's part, like he can't afford to be open because he might not get what he needs. The need to control is the same sort of thing and is also fear-based (that's WHY they sneak, lie, or hide.)
When I have been faced with fear-based behaviors in a child, I've responded by addressing that fear as THE issue. (I view the behavior as a sign or signal of an underlying problem, not as a problem to address in itself.) The behaviors always resolve.
Generally, you could look to issues of control (areas where you may be controlling of him or he feels unheard/disregarded.)
at 8:40 PM on Jul. 7, 2011