ScannerDanner on YouTube has posted several videos of cars that have had engine swaps, PCM swaps, or both when the real issue turned out to be an electrical problem (usually a bad ground somewhere, but sometimes something stranger such as a bad sensor causing the PCM to appear faulty). Code readers are nice, but too many people swap parts based on a code.
In this particular case, it is hard to determine what happened and who was at fault. Someone told the owner the card needed a head gasket, which might have been based on a guess or an actual diagnostic. The owner must have found what he though was a better deal on a used engine, and whoever swapped it didn't check the compression on the new engine. Then some more parts were swapped.