2002 Chevy Avalanche replaced breaks, need parking break don

Actually it is my dads truck. He bought to truck off the lot when they came out. Hardly ever drives it. He had metal grinding from his breaks the other day. Took it in and the rear breaks were completly gone. Somthing about the routers, on top of that his parking break needs to be replaced. He was shocked that the rear breaks went out before the front. He want to know if there has been alot of problems with the breaks on this model.