How do I help stop my dogs separation anxiety?

Unforutently SA is extremly hard to treat, and its not only a matter of training. If extreme cases antianxeity meds are needed. The best way to deter this behavior is actually getting the dog to focus on something else while you are gone. Obviously the kong alone wont help. Is there a room or area of the house you can confine him in instead of a crate? In some cases crates can cause more issues because the dog feels helpless inside it. If you have a room it may help. (You can also try a bigger crate or maybe one of those outdoor kennels/play pens (but inside) , depending on how much space you have, just something BIGGER and less confining). Fill the 'room' with special toys and treats, things he only gets when you are 'gone'. Hiding them verses leaving them out in the open. Keep his bed in this room, its prefered that this is a room he spends time in even when you are home, like a bedroom or den, or so on... That way its not much different. Start off by shutting the door on him when you are home, if hes comfortable in there he wont react much. Keep him in there for a few mins at a time, slowing increaseing. At this point you can use the special treats, whether you are gone or not. This way he doesnt assoicate being locked in solely with you leaveing, its just the place where all the goodies are hiding. When you put him in simply close the door when hes in there, and when you come home just open it as if you never left. This may or may not help, and it seems you've tried similar things. The only other advise I have is maybe getting incontact with an animal behaviorist and your vet. This is a situation best oberved in person and treated in person. It may take a long time. Im hoping ive helped you at least alil.