Reaction to Dilaudid

My father has suffered for years with cronic pain. The doctors believe it is due to nerve damage from kidney stones being removed. Recently his doctor has put him on dilaudid and we are very concerned. His memory has been affected which mimics alzeimers. He does not recognize family members (including his wife), is confused with simple everyday occurances. Also, a man who has always been very patient and mild mannered now has times of beligerence, swearing and extreem subourness.
In one instance he was in bed and we assume he reached for his glass of pop and when my mother found him he was on all fours with his face flat in the puddle of pop on the floor. My mother and sister could not wake him up and they finally got him into bed. They could not get him to wake up by any means until 18 hrs later.
Just last weekend he was up all night talking to "cute little aliens" or "little ghosts in his bedroom. He had full conversations with them and laughed when he said they put on a show for him. At one point he took some money and put it on the blanket box to thank them for the show. He also asked one of the older "aliens" if he could touch the little one because he was so cute. Then he got out of bed and told my mother he could not believe his hand was going right through the little guy. This went on for several hours and when they wanted to leave, my father walked to the front door, let them out one by one saying goodbye and inviting them back again. He told my mother they had beautiful red coats on when they left.
Then he called my brother to tell him the amazing adventure he just had.
We have told our doctor about all of these episodes and he does not seem all that concerned.
What should we do???