The very beginning of the story seems plausible enough.
Security Guard: On the day of the operation, we didn't hear anything coming. We were on guard, but suddenly all our radar systems shut down without any explanation. The next thing we saw were drones, a lot of drones, flying over our positions. We didn't know how to react.
Interviewer: So what happened next? How was the main attack?
Security Guard: After those drones appeared, some helicopters arrived, but there were very few. I think barely eight helicopters. From those helicopters, soldiers came down, but a very small number. Maybe twenty men. But those men were technologically very advanced. They didn't look like anything we've fought against before.
What comes next however... heh.
The "300 rpm" is reasonable, in fact lower rof than what the M197 fielded by the Viper (750rpm min). M134 has a much MUCH higher rof.
Sonic weapons? They are a thing. Never heard of them being mounted on flying platforms though. Not sure if they would work either, but aside from the core effects of such weapons I know nothing about them.
Is there such a thing as "concussion rockets"? We know, because we saw, rockets were fired from some helos. So, taking at face value what that "security guard" said and the whole "nose bleeding, noise, vomiting, etc..."
But "in essence", it is fairly, broadly, plausible.
ish