I have reservations about his statement, but without direct observation, it is difficult to refute the veracity of his claims. I am uncertain about the term "return pipe." A turbocharger typically consists of a clean air intake, boost outlet, and exhaust outlet. There is a remote possibility that fragments from a damaged exhaust side wheel might have entered the EGR system, however the likelihood is minimal. I am unable to comprehend how the pieces would be directed via the intake, given they would need to go a considerable distance through the intercooler.
If I were in your position, I would not abandon that automobile just yet.