Please please please have this baby bile acid tested. Insist to the breeder to have this done. He needs to be checked for possible livershunt.
Some people wont have this done because they dont want to see or hear that livershunt may be in their dogs lines. Alot vets dont know enough to suggest to test for it.
If he has this it needs to be surgically fixed in order for him to survive.
http://www.vet.utk.edu/clinical/sacs/shunt/
If the vet needs advice he can contact the university of Tenn veterinary hospital, they are the best when it comes to livershunt