Additional info for my prior question

Question
I forgot to note that he is on a very regular walking and feeding schedule. He is walked at 730am, 2pm, 6pm, and just before bed at 11pm. His walks are extensive as we have a park right across the street. Breakfast is at 8am and dinner is at 6pm.

Answer
The walking should help.  Some people suggest it as a cure all, and it does help many problems.  

Yours is a tough problem, one I don't have much personal experience with.  It could be if you can just get through a few days and he learns you will be returning soon, it may help.  Also, fill a large Kong with peanut butter and freeze it.  It may keep him busy when you first leave him.  Doggy daycare might work too.