I'm gonna guess driving with the dead bearings did it. Agree that replacing the sensors should be cheap and easy, we just don't have time to do it during the school year. Maybe over winter break, but its not my truck so i don't know for sure.
The weird thing is that the truck drove fine right before the bearings failed. He hit a bump on the highway, then had a problem with the brakes right after, and immediately stopped driving the truck. Then he called me for advice, and so on. He's not an idiot
The brakes were replaced in August, bearings failed in September, so the brake replacement was not due to bearing failure. That being said, the ABS problem very well could be, and probably is.