I'm so sorry to hear about your dog. I just wanted to throw out the disease Lymphangiectasia. It is a very serious GI disorder that is easily overlooked until it is too late. It requires a biopsy of the intestines to verify. While it is extremely rare in the basset hound, I know from experience that they do get it. Anyways, I hope your dog doesn't have it and that he gets better soon.
Russ
Russ