Sadly, I am well versed on pancreatic cancer as my mother in law, Bonnie, has it. She lives with us and I am her primary caregiver. Since her diagnosis last August, I have had to basically be in control of her medical care.
Dilaudid is a pretty good painkiller, but it may not be enough alone. Bonnie uses Fentanyl patches in addition to Dilaudid. The patches help with most of the pain and dilaudid catches the break through pain. Maybe once the pain is under control, your grandpa can get some sleep. Bonnie said that Tarceva (a chemo drug that we used in combination with Gemzar) also helped her sleep.
As far as what else to expect, there's so much! Since we first got the diagnosis, I've been putting out fires right & left. From nausea to jaundice, liver abscesses and diabetes- it all runs the gamut. Things also vary a bit from person to person and definitely in whether or not the cancer is operable (Bonnie's isn't).
I am so sorry to hear about your grandfather. Mine was like a father to me as well. Please make the most of your visit with him. If your grandfather can remain active, that is wonderful! It will probably keep his mind off the cancer and maybe even make him tired enough to sleep at some point. Best of luck to you & your family- feel free to contact me any time!