I think his frontal lob not developing was partly the cause of his parents not giving him the attention and love a growing child needs he's acting on impulse destroying her plants and k*lling her bird because she's put all her love and attention into those instead of him all he wants his mother's love and she can't see that and so the cycle continues. lots of children later diagnosed as sociopaths usually are more understanding that their immediate impulses are wrong and that's due to the attention and love they revieved as a child he obviously didn't recieve any and therefore doesn't know any better his way of showing love is hurting and removing everything that the person he loves or likes cherishes until there's only him left to cherish.