A lot of people have problems after surgery, I don't have the knowledge to help you, but read this link from someone without a gallbladder. //www.curezone.org/forums/m.asp?f=447&i=20119
Go to the bottom of this page and also to the liverflush forum and look up Flowerchild59, the posts are in alphabetical order, she had surgery a long time ago and off and on still has problems, check if they are similar to your father's.