I've had some time to grab some books and mull this over a bit. Ya know I feel like we're giving answers to the wrong question. If your friend has marksmanship issues in the field, should you be teaching him to shoot a good standing, or would he better be served by teaching him to seek the first rock or tree to rest off of to make a better shot?
I shoot a fair offhand in Highpower competition, but what it has taught me is not the mechanics of shooting offhand in the field. My learning has been more cognitive. In spite of my match scores, I know that I will take a carefully aimed deliberate offhand shot in only very narrow circumstances (without better options, no wind, good footing etc.) Offhand has also taught me about trigger control and discipline that is applicable in all field positions.
I could share with you what the highpower champions have said relative to your initial question, but again I think you're focusing on the wrong question for your friend.
