the oil pick-up is clogged and it has sustained main bearing damage on 1999 Pontiac Firebird

A guy selling his car reports this problem. What do you suppose is the real problem and what might it take to fix this? and how much?

Asked by for the 1999 Pontiac Firebird
This really can happen especially to the volkswagen 1.8 litre turbo engine from using reg motor oil when they recommend synthetic oil, The engine needs a complete rebuild if the main bearings are damaged probably $3000 to $4000 for a rebuild