Loud Engine Noise problems of the 2012 Subaru Impreza

My son's 2012 Subaru Impreza, was bought used, with 59,000. Miles, with hope of owning a reliable, safe vehicle on 2/11/16. On 6/26/16 he went for a routine oil change and within one week the car was completely seized. He was driving home, no warning lights, or anything just made a loud sound then he was just barely able to make it to the side of a busy 3 lane road to call for a tow truck. At the time, we worried that the oil change may have been done improperly and caused the issue. We contacted the business, who then had a ase certified mechanic/inspector verify that it was not the oil change but an internal engine problem. We then had towed it again to Subaru dealer that was 7/12/16. Then we began calling- daily or every other day; to the service manager and emailing to corporate Subaru- asking what is wrong with his car? why did it happen? what can be done? what will it cost? finally, on 8/22/16, we heard from Subaru saying that the vehicle was outside the warranty -but will authorize a $2,000. Toward repair or new car. We called the dealer again because we still had not heard or received a reason/quote of repair. We were told that it was damage to a piston and it would cost at least $10,000. And they did not recommend it; better to talk to sales. The warranty is for 60,000 miles or 5 years on the powertrain, we are at 67,000 miles and 4 years. So now we still owe $8,000. And have $10,000. Repair, and they are offering $2,000. Money vs safety and now vs trust we want a safe reliable car, from a company that we could trust. We thought that was Subaru.