My DS is 3 and a half. He has a diagnosis of Autism. He is going through a funny phase of having an urge to knock things over. Mainly the big bar stools in our kitchen he also can't help but drop the nearest thing to hand into your tea/coffee etc- mostly lego pieces. I know he is not being naughty he really can't seem to help it. What is he getting from this?, any ideas on what I can do to help him.