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.
The story doesn't give a specific identity to the old man. He might represent any individual who has the determination and vision to make a difference in the environment through the simple act of planting trees. So, he could be seen as a symbol of environmental stewards in general.
The old man in 'old man at the bridge story' is important because he is a microcosm of the impact of war on the common people. He has a simple life before the war, taking care of his animals. But when the war comes, everything is taken away from him. He is a character that elicits sympathy from the readers, and through him, we can see the larger picture of the destruction and despair that war brings to the civilian population.
The 'old man' could be a grandfather figure, someone who has lived a long life and has a lot of stories to tell. He might be sitting by the fireplace, sharing his tales with his grandchildren.
Well, the movie doesn't give an exact age for the old man. But from what we see, he seems to be in his late middle age, maybe around 55 or 60, judging by his looks and actions.