The old man Tim has seen in town for years turns out to be incredibly important.
Years back, when Tim was still hanging out with the Mystique crew, a bunch of happy little conservative literary rebels (if such people can ever be called something besides the mainstream), he had the distinct impression, upon graduation, that his life was at a crossroads, in which he could attempt to stick around with them and find out where that led, or split off and create a far more hazardous destiny. The part of him that wondered where the happy little conservative literary rebels (if such people can ever be called something besides the mainstream) knew there was a mystery waiting to be explained in that direction.
By the time he's learned the old man's secret, Tim understands that he might have found out years earlier if he'd just gone that way.
All of this makes sense, I swear. This is to say, Tim found out that the old man may in fact have been God, and that when the old man dies, the whole of existence goes with him. It's a starling, instantly sobering thought, one that occupies Tim, as all his deepest thoughts do, for quite some time, becoming an obsession that constantly threatens to consume him whole.
It doesn't matter how little Tim actually thought of the Mystique crew, that bunch of happy little conservative literary rebels (if such people can ever be called something besides the mainstream). Even though these were the years in which he took his first tentative steps into the breathing world of letters, Tim suspected immediately that his friends were all frauds, worse than the pretenders who wasted everyone's time in class. He knew he'd never know personally anyone who was a great writer, certainly not from those years.
When the recriminations came, later, among a crew of still less-talented writers, backbiting, backstabbing, egomaniacs sure of their own divinity, he observed with irony how none of them considered for a moment that there was such an individual as the old man in the world.
And how would they have reacted? Just as if it were the end of the world. How appropriate, surely? Tim spends most of his days now wondering when the old man will die, and what will happen when he does.