mega-esophagus?

ME He was doing very poorly in spite of all efforts to put on a little weight. Even with proper positioning for 15 minutes after each meal or drink, he failed to gain. I had to let him go. Very sad here today.

So sorry to hear about the loss of your puppy. I had the same situation, which is why I recognized the symptoms, and lost my puppy at 9 weeks old. It's one of the reasons this is called a "heartbreak hobby".