You can look up the gear ratios on Sheldon Brown's site to see how big of a jump it would be. Once you figure out what the easiest ratio on the new bike will be, make Mr. ride up that 25% using that gear ratio equivalent on his current bike. That way you can see if a compact double with that gearing will work for you, where you ride.

I did this when I bought my new bike and got a compact double on it. My compact double lowest gear is about 10% taller than the lowest gear I have on my triple. Once I ordered the new bike, I just stopped using that lowest gear. I missed it for awhile, still do sometimes.

V.