Should this have been an actual hostage or person with a gun situation they would have needed far more than one car and a few officers to deal with the incident. Cops don't go in with minimal forces assuming it's a hoax, and you sure as heck wouldn't want them to if this had been a real emergency and your family actually was being attacked. Nope, you'd want the entire cavalry to come a-running, and you wouldn't want them to waste time trying to trace the number the 911 call came in on first.
They rightly responded a ton of officer, the helicopter, and probably the fire department, an ambulance and a whole bunch of other folks were on their way. And once they got there they had to assume it was a real call until they cleared the entire house. And if it had been a real emergency and they'd responded with less than everything and everyone they needed to deal with it, we'd be looking for someone to blame and calling for that person to loose their job.
I only listened to the video right up until your brother started arguing with the cop at the door. It's not enough that he tell them everyone is okay. He was in the wrong to do so. If you and he don't understand that then we can't fix stupid. We tried, but our big boy words hurt your feelings.
P.S. How did your brother know it was a prank so quickly, as he told the officer about two minutes into the recorded conversation? Somehow, I feel there is more to this story than you got swatted out of the blue and have no idea where it came from. Maybe not, but you'll get no sympathy around here after how he acted.