I'm not sure which specific 'crazy old man dnd story' you are referring to. There could be countless Dungeons & Dragons stories involving crazy old men. Maybe it's about an old wizard who has gone mad and is causing chaos in the game world.
There was an old man in a DND setting who was a former knight. He was old and frail but still had his honor intact. A group of bandits was terrorizing the local village. The old man, despite his age, took up his old sword and shield. He joined the villagers in their defense. He taught the villagers some basic combat skills. In the end, they managed to drive off the bandits. The old man became a hero to the village once again, just like in his younger days.
Another plotline could be that the crazy old man was wronged in the past and is now seeking revenge in a rather unhinged way. He might be using his old age and the element of surprise to outwit his enemies. He could be creating all sorts of traps and illusions to get back at those who wronged him, and the players get caught in the middle of this revenge plot.
An old man could be a gatekeeper. He guards a mysterious portal or a secret passage. Only those who can solve his riddles or complete his tasks are allowed to pass. He might have been placed there by an ancient order to protect something important.
Since we don't have much information about this specific 'blackkklansman old man story', it's difficult to say who the old man is. He could be a fictional character created to represent the older generation's experience with the KKK - related events in a story based on 'BlacKkKlansman'.
In 'the old man at the bridge story', the old man is an ordinary person whose life has been upended by war. He seems to be a bit forlorn and lost. He has his own little world back home with his animals, but now that world has been destroyed by the war. He is at the bridge, a sort of liminal space between the past and an uncertain future. He represents the countless individuals who are displaced and left in a state of confusion and despair during times of war.
There's not enough detail to know for sure who the old man is. He could be a variety of things. He might be a war veteran who has some skills or knowledge that comes into play in the story. Or perhaps he's an old family friend of one of the characters, and his presence in the story is to provide a different perspective or a connection to a past event that is related to the events in 'Equalizer 2'.
He is a character who embodies the despair and displacement brought about by war. He's an old man who has been through a lot. Maybe he had a simple life before the war, but now all he has left is the bridge where he sits. He doesn't seem to have any strength or motivation to move forward, and his presence at the bridge is like a statement about the state of so many people during war.