Just looked through the posts albeit quickly so sorry if its been mentioned before but what are you feeding him, he needs to be on an adult ,good quality, natural diet low protein i feed burns my youngest had been on this since she was 5 weeks and she has been the easiest of all mine, you have had some excellent advice on training but if fed a food with lots of additives and chemicals can make them hyper and less focused during training so do check the food content.