Steve, I'd be happy to try to help out with your friend, but have a couple of caveats.
First, I'm ultra-new to Flidigi, so if there is another Mac user who is more experienced with it reading this, I'd definitely defer to them.
Second, in my experience with Flidigi and WSJT-X, the issue isn't so much the basic install of the program, but rather getting it configured to talk to your radio, and getting the radio itself configured. If your friend happens to have an IC-7300 I can probably help, but if he has another radio it might be more beneficial to find someone with experience with that particular radio (whether or not they're a Mac user).
Finally, I haven't installed and am not using Flmsg, so I can't help with that.
Despite all of the above if it seems as though there's a way I might be able to assist, let me know!