Sorry to hear about your husband's pain during recovery. I had a modified whipple surgery, liver resection, and liver ablation in 2019. I left hospital at 14 days with a drain in, that was draining around 240ml a day. I had pain in my left shoulder in the front that would come and go. Over the counter pain medication helped enough to make it tolerable but did not get rid of it completely, so your husband's pain sounds alot worse. I was back in the ER after 43 days with intolerable pain on my left side, it was very sharp like something was stabing inside me. I had a CT scan and blood work, and they checked for blood clots and that my drain was still in place and working, they didn't find anything to explain the pain. No blood clots, no fluid collection, no infection. I was relieved to know that the CT showed no problems post surgery. The terrible pain lasted for over a week, the only time I wasn't in pain was when I layed perfectly still. Which doesn't help for recovery, ER gave me hydromorphine to take home for the pain which I decided not to take as I had a horrible 4 days when I stopped taking it previously. I was finally completely pain free at four months and that was also when my drain finally healed on its own. I would discuss the pain with the surgeon, I have read in the past that shoulder pain can be from air remaining post surgery. My recovery was slower then I was expecting, just made sure I was up and walking as must as possible. I did meet with a dietitian post surgery to discuss the easiest food to digest, and I needed to go on pancreatic enzymes for the first few months. They did help but was happy to get off them, found it difficult to get the dosage right. At 6 weeks I was disappointed with where I was in my recovery but I slowly improved. Wishing you and your husband the best, hopefully your husband will turn the corner soon.