First of all I would have someone other that your BF asses the fit of his loaner. Having coached many women over the years, I have seen so much frustration because someone was on a bike that was too big or too small to start with. I get not buying a new bike; just make sure it fits.
Here are my other recommendations:
Skip the clipless shoe/pedal combination. The new mountain biking shoes with sticky soles work so well that there's no reason that you should use clipless. You will be much more confident if you can put a foot down any time you want.
Basic skills: Now I don't know what kind of a guy BF is. Some guys are great teachers, others are more of the "don't grab your front brake and just point it down the hill" type. There are a few basic skills that will really make a difference for a beginner.
-Braking: how to do one finger braking, feathering and using modulation (gentle squeezing)
Basic Body Position: is NOT sitting on the saddle. Mountain biking is very dynamic and involves being loose, moving with the bike and terrain, and changing your center of gravity. This video here,
https://www.youtube.com/watch?v=tAkB...M&feature=plcp is excellent instruction in body position basics. Don't let the big bikes or big air in the into scare you - what they teach in the video is the very basis for all successful mountain biking.
-last but least, you might look for a basic skills clinic. I cannot underscore the foundational skills for mountain biking success.
I.