I think the boy in the video is the younger spirit or essence of the man in the chair. His younger self is so disappointed in the adult he turned into. The X's on the wall is just the passing of time as the older self sinks lower & lower into a life of idle sameness, loss of his wife from leaving him, and despair. The same scar on the hand shows they are the same person and when they can see each other, it's after the older man has left his body from death. I think them walking down the stairs together is the man and his younger spirit self walking into the afterlife together.
I think the boy in the video is the younger spirit or essence of the man in the chair. His younger self is so disappointed in the adult he turned into. The X's on the wall is just the passing of time as the older self sinks lower & lower into a life of idle sameness, loss of his wife from leaving him, and despair. The same scar on the hand shows they are the same person and when they can see each other, it's after the older man has left his body from death. I think them walking down the stairs together is the man and his younger spirit self walking into the afterlife together.