A couple of things I still remember about him.
And no, he was not disabled. I saw him in other roles. That's how good he was.
One time his character shredded important documents and he might have copied the documents he was supposed to shred. He was given the two groups of papers and told to do the job too quickly. One of his co-workers (I think a lawyer) confessed and got yelled at. Then the guy admitted he really did it and said he would leave now. I think it was the old man who said he wouldn't have to go anywhere. Did they fire the other person? Of course not. He was important to the firm.
And then there was the time terrible things were happening. It might have been that the firm was shutting down which would have been the end of the show. Whatever it was, he couldn't handle it and he started getting violent. One employee wanted to call security. Another said they needed to just show him some compassion. After all, he was doing the things they all wanted to do.