My son bought a 1994 pathfinder from a private owner. When he took the car to a garage for exhaust work he was told the frame is shot and it shouldn't be on the road. He took the car to three different places and they all told him the same thing. He's had the car less than a month. Does he have an legal recourse to get his money back?

Your son probably has no case, because in almost all sales like this the merchandise is sold "as is." Especially for a 15-year old car - your son should have had it inspected before buying it. But it really depends on whether there was any sort of warranty or guarrantee that between seller and buyer. If the seller made a specific representation that the car is in road-worthy condition, then your son may have a case. But to carry any weight the warranty needs have been specified in writing on the bill of sale. Otherwise it is unlikely that your son will ever win anything.