I had to Google it. Mr. Pembrose is the eyeball lying on the couch. Lacking a body, he is physically incapable of doing anything. That's why he's angry at the world: he exists but can barely participate in existence.
I was just thinking the guy’s been so beaten down by life he’s been reduced to an eyeball. But a lidless eyeball cannot help but appear angry, so the psychiatrist is labeling all the horror that sliced him up as “eh you’ve got some anger issues”
It's hard to spot, but Pembrose is an eyeball on the couch. It's absurdist humor - of course if someone were just an eyeball but somehow sentient, they'd probably have a lot of anger towards the world.