That is so sad he is so aggressive dont give up on him...
Bach Flower essence...I just posted this on another thread
worth a try...I know of a few breeders that use the remedy (which is a mix of five essence) I havent used it but they live by it!
http://www.nelsonbach.com/BFE_for_pets.html
these flower essences are used singly or in combination (e.g., Rescue Remedy) to treat various behavior problems including anxiety, or when the animal's mental condition needs to be changed. The essences are generally given by placing several drops of the essence into the drinking water