I live less than a mile from where this happened. I'm not familiar with these specific roads as this is a gated community, but I know that the road type is the same as where I live.
The roads are unmarked concrete. The speed limit on this road was likely 30 MPH
There is no way that any AP features would have been able to engage on this road. I tested it out on my street and a bunch of other neighborhood streets last night. Was trying to see if the center expansion joint of the concrete would fool the computer into thinking that there was a center stripe. Nope.
The next fact you have is that the crash somehow caused the car to burn. Either this was a total fluke or they got going REALLY fast.
That road is not very long, and also not very straight. So they weren't accelerating for very long in either direction.
Next, this wasn't two kids making a YouTube video. It was two guys, one 59 the other 69.
Finally, I know not everyone's on the forums, but I haven't heard of a single FSD Beta of anyone in TX.
I'm not sure what happened. But I'd be willing to bet a bunch that the car straight up crashed and either 1. There was another person driving who got out and isn't fessing up or 2. That the driver tried to climb out the back to escape the crash / flames.