he developed a fever of 105 and it has not went down in 4 days.
IMHO, your first course of action should be to contact your dogs breeder. Whomever you acquired your dog from may have information regarding similar health issues with other dogs within their breeding lineage. That information might help your Vet with your pups care. That doesn't make it your breeders fault. Even human babies sometimes get cancer. (Think St. Jude's.)
Since your pup is at the Vets office getting poked and prodded (and not with you), he may be extra nervous and upset. So, theoretically, the fever may just be a natural response to the anxiety he's feeling.
I think all of us appreciate that this is an incredibly upsetting and frustrating experience for you. Please keep us updated.