Hi,
Sorry to hear your dad is still suffing so much pain, I know how you feel. My husband had a whipples operation in July 2007 and is still getting severe stomach pain, his chemo has been stopped half way through the 26 week course so that they can try to find out the cause of so much pain but it has taken a long time for the Doctors to listen to him and start investigating.
You don't say what kind of pain relief your dad is taking. If it is any help my husband is on 150 ml Durogesic patches which he changes every 3 days, he takes copious amounts of Oramorph and CoCodamol tablets. He does have good days but the pain never goes away completely.
So far he has had a CT scan which has shown no obvious cause for the pain and is awaiting an appointment for a laproscopy, but being the British Medical Profession it could take months. Where are you from? you may have a better health care system.
Diet and weight gain is a big worry, it took 7 months for my husband to eat any savory food.
I wish I could offer more help I know how hard it is to try and find help and for somone to listen to you. My husband is sitting here with me now and says to tell your Dad to make sure he takes all the pain relief given to him and make the best of the good days because he will get them as time goes on. He also says look back at the the months or even weeks and see how he has progressed since his surgery even though it seems slow, they may seem like small improvements but they are massive leaps post whipples.
Mandy & Pete