Oh yes.
He's reached so many new levels of bullshittery that he's practically in orbit now.

no such thing as orbit
Light doesn't get "reflected through things" it gets reflected off things and changes direction as a consequence. The phenomenon of light bending as it travels through media is refraction, caused by the differing densities of the media slowing the light down (until you get to the critical angle then you get total internal reflection - at least for some materials). However as you have already stated light doesn't have speed it cannot be refracted as a further point i am not sure it can be reflected as it is reflected by striking objects in the path of the beam and as it doesn't travel how can it strike something as it is already through it and way past onto infinity.
Cheers for posting about that, it was something I was meaning to say.
Refraction is well known and exists, so is often used as a convenient reason for why flat/non-globe earths work, how we see sunset, why ships disappear over the horizon, why sunlight on a dome does not illuminate the whole world etc. Hey, that would need light to bend consistently your model doesn't work. Refraction - job done in one word.
However the key thing is that bit you say about going through materials of different densities. The density of substance A can be measured and so can the density of substance B, as can the angle of light entering B from A. Then guess what? Like the rest of physics there is repeatable, testable maths where you can work out and predict exactly what will happen, and like many things on this thread, you actually go into that at school level. It is not black magic for elite scientists, it is what kids do, then they do an experiment with glass prisms to verify the maths work and they are not just being told something.
So, if light was going to bend by 70 degrees over a certain distance and we know the density of air at the surface (based on current conditions) we can tell what the different densities though the higher atmosphere should be. However actual recorded densities do not lend themselves well to some of the magic bending light required as the dome earth bodge.
This is especially so in the event of a solar eclipse where the light from the super carbon arc bounces off the dome but after a bit, does a complete 180 degree turn and comes back at itself exactly in a way which is completely in phase so it will cancel itself out. No intensity is lost. To quote Douglas Adams, it is all clearly a load of dingoes kidneys.
Then you have to consider changing atmospheric densities and how they change with weather but many flat earth effects stay the same. Hmmmm