Why WOULD they replace the…
Why WOULD they replace the entire truck when it is only the engine that failed? What does the owner mean by "the truck will never be the same"? It should be even better with a brand new engine. Then the owner adds, "I couldn't care less about a warranty." What kind of fool are you? If the replacement engine fails, you'll get a new one, and if that one fails, you will get another one, and so on, until the warranty expires. Thank your lucky stars that GM stands behind the warranty.
There are a number of complaints regarding the 2.7 Turbo Max engine problems but as yet there is no recall. My advice, enjoy your new truck until the warranty covering the engine expires and then sell it. (and only use fuel with a "Top Tier" rating if you want your injectors, rings, etc. to remain free of sludge & carbon build-up, and your engine to last).