Well, I have not had time to look up many of his claims, but here are the arguments I did.
The comet tail argument is silly. In this video, the guy cliams that the movement of the comet causes comet's loss of mass. The way he describes this is with a snowball being thrown and loosing mass. I really don't know what to say about this but that his ideas of what causes the comet's tails are very wrong.
Astronomers attribute the comets degeneration of mass to the radiation emitted by the sun (This being the cause of the dust tail and the ion tail of a comet), which is the reason the tail points away from the sun.
Anyways, the fellow describes this loss of mass as constant, which is one thing that is wrong. A comet closer to the sun would experience more intense radiation and would lose more mass per unit time than a comet farther from the sun.
In this way the rate of the loss of mass of a comet is not constant but variable, the maximum being when the comet is at the closest point to the sun in its orbit (there is a name for this characteristic of an ellipse, though I forget what it is).
The orbits many of the long lived comets are very large and extend huge distances outside of the solar system.
He argues that large comets have lifespans of thousands of years only (have been able to find anything confirming this.) The Hale-Bopp comet, for instance, has a 4,200 year period (The period is the total time to make an orbit). Considering this is not its first perihelion, the very fact that it has been around this long and its unremarkable size is very contrary to his ideas of how a comet should lose mass. This is described here (and on the wiki page about this comet):
http://science.nationalgeographic.com/science/space/solar-system/comets-age.htmlAnyways, the point of this is he seems to disregard the possibility that new comets can form (In reigons such as the Kuiper Belt and Oort Cloud). I might agree that if NO new comets were formed for billions of years, that the ones that existed may have sublimed away, but that just is not the case. That part seems to hinge on the assumption that (if the 4.5 billion earth is correct) all of the comets in existance were formed billions of years back and should all be that old. He also makes some incorrect claims as to the "ice and rock mixing" to form a comet, and assumes that comets are God's creations therefore.
His analogy for how a comet shed it's mass is kind of stupid also, because a few minutes back in the video he makes a big point to explain that space is a (practically) friction less enviornment. What else would cause the comet to lose that much of its mass but the solar wind? (Should not the dust/ect. otherwise be attracted to the nucleus of the comet because of the gravitation caused by the mass?)
Many of his other points hinge on incorrect conclusions.(I believe he disregards the fact that starlight takes a finite amount of time to reach Earth depending on their distance from Earth). He also claims Earth is the center of the Universe. But the whole video is just so long and wrong that it would take some time to discuss everything wrong that he said.
I'm not an expert on astronomy or physics so I may be wrong on some points here.