Weight loss

It's important to get to the root of the weight loss. Is it that he's simply not eating enough despite the appetite stimulants? Or does it seem he is eating plenty but losing weight anyway?

If he seems to be eating enough, his pancreas might not be producing enough of the right enzymes to properly digest food and extract nutrition from it. Or if there's a partial blockage of a bile duct, there might not be enough bile to do the job. There are simple liver and pancreas blood tests for this. Changes in stool color, flotation, greasiness, smell, etc. can be big indicators of these problems. I lost 30 pounds before my pancreatic cancer was diagnosed in part due to these causes. I regained all the weight after a bile duct stent was placed.

If he's just not eating enough, you might be able to get temporary supplementation with a PICC or Central line to infuse nutrients intravenously. When my pancreas tumor came back (after Whipple) and blocked my stomach outlet, I went several weeks without eating and again lost 30 pounds. Finally, a "Central" line was placed in my chest, and I had a 2000-calorie bag of nutrients and hydration ("TPN") pumped into my veins over a 12-hour period every night. After a gastric outlet stent was placed, I slowly became able to eat an almost normal PO diet. Between the TPN and the PO, I again regained all 30 pounds.

Doctors seem reluctant to place invasive pathways like PICC/central lines if other options exist, because of the potential for infection, but they might be underutilized, if you can keep a patient from crashing due to poor nutrition. That's no fun, speaking from experience. You should definitely run these thoughts and questions by his medical team.

Creon enzymes, eatent with each meal, helps my wife's pancreas with digestion.
Then Kates Farm a a protein shake snack also helped.
She tried Glucerna, but as its dairy based it aggravated her GI and the diarrhea offset the benefits.
Kate's Farms option expensive but so far, less diarrhea, and maintaining weight.