losing weight without trying

my husband age 54 has lost 30 pounds in 5 weeks. he is so week. he was dx in 1993 with hep c and in 2003 with cirrohsis of the liver. 2 weeks ago he had an ultra sound of the pancreas and they found a mass the size of a golfball on the head of the pancreas. so they did a ct scan and the doc. said it is a cyst and that his gallbladder is swollen, that's it. but why does he feel so bad, week and losing so much weight?