As a cancer survivor who received intense chemotherapy and radiation, I can understand your husband's fatigue. It is a tiredness without comparison. From the information which you have provided, your husband has hyperlipasemia. The high lipase levels can be caused by pancreatitis or tumors of the pancreas. There is pain associated with tumors of the pancreas. Gallbladder infection and kidney failure can cause hyperlipasemia.
Recommendations are to avoid alcohol, eat a diet low in fat, low in red meat and high in fiber and keeping well hydrated by drinking two to three quarts of fluids each day. But, do consult with your husband's oncologist regarding any dietary guidelines. At this time, maintaining good nutritional status and keeping well hydrated is very important and can be challenging. God bless both of you.