My son took his 2011 Jeep Wrangler for an oil chan...

My son took his 2011 Jeep Wrangler for an oil change and 2 weeks later his engine is blown. Pep Boys, W. 38th Street, Indianapolis, In. They refuse to do anything about it, said it's not their fought. We took it to a Jeep Dealership and they stated that it had no oil in it. We have contacted an atorney.it has been 2 weeks and no help and my son is without a car due to a simple oil change