Erm... the idea is that he's going to change his training regimen, and pretty much spend all of next year working on his TT skills. A big chunk of TT'ing is also strategy and bike handling, skills that can be developed.
Pro cyclists also do change disciplines, many times with success. Lots of well-known GC guys started out with mountain bike racing, and there are also some track cyclists who've made an excellent showing lately, e.g. Bradley Wiggins.
Besides, it's not like he's saying wants to lose 75 pounds and become a climber.
And the worst case scenario is that it doesn't work out, and he decides to go back to sprinting. I say he should go for it.