captive-ntfs is safe because it uses the Windows driver to write, so there shouldn't be any problems. (I can't get lufs to work, though, which it needs.) Knoppix does have it, but I'm not sure if they can include the ntfs.sys file. You may need to use captive-install-acquire to get the file from Windows or download it from the internet.

Had something similar before hand.

I used a Ubuntu Live CD and all i needed to do is mount his NTFS partition read-only and copy the files over network to my server with scp.

That is about it really.

The problem he had was with dynamic windows (stupid) partition. In the end, after backing everything up I managed to recreate the partition on the drive and the all his files were back on the drive.