I'm so jealous that you'll do it for her. My friends REFUSED. My husband is probably 1000x more sentimental than I am, and he really really wanted to go to the shower but the ones hosting it said no. (if that happened to us *now* there would be a very different response)
MY main reason for wanting a coed shower was that I despise normal baby showers with a huge, burning passion. And that's what I ended up having.
A shower with men there NEEDS to become something other than the typical shower with ridiculous games etc. It needs to be more of a celebration, a happy, looking-forward time, with gifts for the baby and LOVE for the new family. Not "what's this in the diaper" nonsense. (although DH being DH, he would have loved that, too...they should have let HIM have the shower and let me go off and do other things, frankly!)
Anyway, good for you for wanting to give her what she wants! And congratulations to her, too.