I know the first and 2nd gens were famous for either breaking exhaust manifold to head bolts, cracking the exhaust manifold or lifting the head off the deck because the heat expansion and contraction that is why the 3 pc and 2 pc aftermarket manifolds are sold. He might once he gets the manifold off to have them check it for warpage. But it sounds like they are blowing smoke because it should still be under the powertrain warranty which should cover both parts and labor. I would suggest he pull out the warranty booklet and start reading.