The inclination of the Earth's according to the gentleman is cyclical shifting by about 2.4 degrees every 41000 years and back. That is consistent with the historic observations of building pointed to the North Star as northern marker throughout history. The last time the cycle was on its starting point was in 29500 BC (as far as we can tell), which means that since then, give or take 2 degrees, the North star was a known and only reliable geographic marker that existed throughout the ages.
Another good indicator that there were not many variations in known history is the Nebra disk, which also corroborates that the firmament has not changed all that much.
And, last but not least, the Earth axis at this point in time is 23.4 degrees, which all good astronomy programs I know reflect accurately and according to Milankovitch axial tilt the end point is 24.5 degrees, not 26. Something you could find out really fast by googling it. Around 18000 CE we will know whether he he was right.