This is a huge pain. Not as easy as it sounds. Honestly, would be easier if you had access to a PC system as the tools are better, drives are faster and process is more streamlined.
First, you could simply stream the movie through HDMI from a player to an HDMI capture card, but I don't know what your options are there, hardware-wise. Probably expensive for good quality. You are looking at 30-50 GB per disc.
Second, you could buy a USB bluray drive that is mac compatible. Apple does not make a blu ray drive and offers no software. Aurora makes player software and a free ripper, but that produces a hard to handle or edit .bdmv file. You are better off with
www.makemkv.com/ which will create an mkv (matroska) video file of your bluray video. From there you would need to convert it using VLC, handbrake or maybe ffmpeg for editing. That conversion is tricky itself, and time consuming.
Honestly it may be easier (and cheaper in terms of hours) to just keep pursuing a digital master. He must know what house made his blurays or have a producer make a call. Is it sold in a digital format online anywhere? an itunes .mp4 could be ideal.
-TG