Stealing

This sounds like there could be what we would call a compulsion. This is by no means a diagnosis. But until a full psychological evaluation by a licensed psychologist is conducted, we would just be guessing. Stealing is sometimes a behavior we use to get something we want. Sometimes we steal to get back at someone even though we don't need what we stole. Then there are instances when people steal because they have no on/off switch to compulsion - a need to do something without there being a clear function to the behavior (eg. checking the door locks at night 5 times before going to bed). Thankfully, you are an observant, thoughtful parent and are doing something about this very early on. 

A good evaluation by a licensed psychologist will provide you with a diagnosis and set of recommendations. A good case manager can help ensure that those recommendations are followed-through with by finding the best therapist and psychiatrist available as well as coordinating with any other professionals needed. 

In summary, judge your son's behavior and not your son. Let him know you all are on the same team and will develop a plan on how to find a healthier way to express whatever is going on with him. Get that evaluation done and you'll have some clarity and direction. 

Best of Luck.