Suburban brake repair

I recently had a friend help me replace my brake pads on my 97 suburban and in the process he also had the discs and drums turned (is that the right word?). This was less than a month ago and less than 2000 miles ago. I just noticed that my brakes feel really bad - metal on metal. I took it back over and after taking the brakes apart, he noticed that the pad on the driver's side have almost completely worn and the pad on the passenger front are completely gone and the disc is scored.

Although he knows a lot about cars, it seems too coincidental to me that the brake pads on both sides wore so quickly after the change and that there may be something that is specific to suburbans that maybe was overlooked in the pad replacement. Any ideas would be greatly appreciated as I don't want to repeat the same situation in the next 2000 miles.

Thanks for any help