It's wicked to mock the afflicted

There is an old man who wanders the halls at my new job. He is hunched and mumbles to himself. His belt always misses a loop in the back. My guess is that he is a well respected member of his chosen field but by appearances he would be at home pacing the corridors of a dementia unit. I've tried to be friendly when we have passed each other in the halls and have never managed to register an acknowledgement of my existence never mind an articulate response.
I went to the break room yesterday to read a cup of tea's worth of my book. Our grumpy gentleman was there muttering to his coffee. I asked a cheery "mind if I sit down?" to which was replied a series of unfathomable noises albeit at a more conversational volume signaling this was not part of his unending mumbled soliloquy. I sat down with my book and tea and as if we were on a see-saw he rose with his mug and left the room trailing behind him wisps of grunts and mumbles.