So in the video VSauce goes into a deep explanation of the past happening or not.
Of course, we cannot go back in time to actually find out if it actually happened. Until we get a time machine of course. But who knows when that'll be.
He then starts to talk about energy and how every single movement we perform on earth will eventually cause a heat death. Which is the eventually distributed energy throughout the universe. Once this happens, nothing will be able to happen in the universe because it needs entropy to perform such task. Eventually causing the death of the universe.
However, what he didn't mention was how this was connected to the past really happening. Yeah, we could say that the past is the result of the soon to be heat death. But how would that describe the past really happening? Did it happen? Is the Heat Death obseravable? If it is, then obviously my question would be thrown out the window. He seemed to move on to a new topic. Maybe that was his intention, to see if we would really remember what he was talking about. As the video states,
Did the past really happen?