Have to tried using the log and transfer feature inside of FCP7? Should be under File < Log and Transfer. Either have your camera plugged in through firewire, or transfer the contents of the card into a folder within your project folder and open those clips. Should transfer fine into a more editable codec such as Apple ProRes.
If that doesn't work MPEG Streamclip, like someone said above will work. Best thing is that it's free, download here http://www.squared5.com/.
I use to use mpeg streamclip to convert my dslr footage to a codec that would be accepted in FCP7. Never had an issue with loss in image quality, just make sure you match all of your settings from your native video. MPEG Streamclip is easy to use, but if you have trouble figuring it out I'm sure there are plenty of tutorials on how to use the software on YouTube. Hope this helps!
Also just curious as to what make and model helmet cam your friend is using?