Remembering the tow vehicle was not designed to be a tow vehicle. Says so right in the owner's manual under 'Towing.' The brakes are more than adequate to stop the 30,000 pounds of the loaded rig. And yes, the trailer does, and must, have its own brakes in the 5,000 weight range. So I get some choices: reduce, as I can, the 30,000 pounds of the RV and manage the trailer weight to keep within the capabilities of the brakes and loads on both vehicles.
The reason that I am delving into this is that the pro trucker that moved my loaded trailers to Nevada commented on the fact that they were seriously overloaded and dangerous even for him to tow. I am not a pro trucker. Managing the weight and length of a large RV, without the trailer is a handful. Add the loaded trailer, and the the combined weight and length commands my undivided attention. This pro trucker is also a member of my congregation, so his advise and counsel is close at hand, and he has expressed nothing but admiration for my endeavors. In other words, I ain't getting shined on. I am fortunate to know him. On other thing: what I am piloting down the road is my entire world. There is no 'home' to return to as the wrecker carries off the wreckage.
Your Astro van has braking capabilities for its intended function, Bart. So does my RV. Not an apples to apples comparison between the two if all we compare are the final numbers. The intended functions differ.
As I said, this is getting interesting.