proof is definately the way to go, that's the end your concerned with. Spend hours on colour correction here and a lot of it is workin, blind using comparative differences between amount of cyan etc and trying to extrapolate out the percentage difference to apply to what's on screen.
Now that was a garbled but you get the idea. As for why it's so different, not sure, but quite a lot of programs will display differently , photoshop, flash, illustrator. It also depends greatly on your monitor callibration compared to his as to how wrong he thinks it looks (though from your examples there's obviously a difference between programs), you never know.
Colour's a bitch. Proof.