Other than a lemon case, can an "as is" car be returned due to a possible false credit report?

I have a friend who bought an "as is" car 4 days ago. He has just been in the country for two years, not much credit history, and still very inexperienced. At first, he was told that he needed a co-signer because of lacking credit history. Later on, the dealer somehow managed to get a FICO score of 740. Is this possible? To make things worse, he signed all the papers without even reading (or maybe did not understand). He neglected to notice a discrepancy with the odometer as stated on the report.