aside of the overkill energy, the author messed up a whole lot of other physics.
1000km is a quite noticeable 17% of earth's radius, way above the atmosphere. that's low earth orbit. the fall would take 7.5 minutes at 1 g or over 8 minutes accounting for the 25% reduced gravity it starts in, not 5 like author said, and in the mean time earth's surface would have moved 200 km on the equator, less on other places. because the linear difference between the velocities of the start and end points is the same 17% (assuming earth-sized planet) it is impossible for something to just fall straight vertically from there, it'll always have to take an arc path of some sort. so it'll be impossible for him to aim precisely without some trial and error first. or some math, which both he and the author are clearly incapable of.
the small rocks they were shown gathering also didn't seem anywhere close to 6 tons. if it were a few hundred kilo rocks dropped from a few hundred meters it'd still be powerful enough, easy to aim, and air resistance would not have any effect so he wouldn't need to handwave that part away too.