Not sure what device you're using, but on my iPhone if I go into iTunes I go to More (at the bottom) > purchased > and there I can see my wife's info. When I click on hers I can see Music, Movies, tv shows.
It's official, Family Sharing doesn't work with iTunes Match
Just spoke to a Senior Advisor at Apple and it turns out that family members can't see music from iTunes Match. They can only see music purchased from the iTunes store and even then they have to download it before they can play it. This totally ruins Family Sharing for me. Now I have to log into my account on the kid's devices for them to see all of the music, but because the iTunes and App store logins are combined in Settings I'll effectively be disabling the whole app approval process. I see two solutions to this issue. First, Apple could enable the sharing of iTunes Match since I already own the music anyway and am allowed to have it on multiple devices. Secondly, and less desirable, they could separate the iTunes and App Store logins in settings. I'm off to disable Family Sharing...