Not much, he's medicated up the wazoo.
When they did my knee surgery, it was spinally anesthetized (because my stomach wasn't empty).
Got sedation from dormicum (midazolam) plus ketamine. The midazolam is just a benzodiazepine, but ketamine is weird stuff....I remember joking around with the guys from the operationroom, then I fell asleep. I got many patients addicted to ketamine, now I know why from my own experience. It felt kinda good, even at the state I was in.
The post-op pain was terrible: got morfine first, then tramadol, then diclofenac.