I have a student who is struggling with flipturns!

If it's pre-competitive anyway... why not give the option of open turns; and coach them on an effective open turn? I did open turns for years and just taught myself flip turns because I've only started taking my swimming seriously in the last couple of years. As the student becomes a stronger swimmer and wants to swim competitively, the flip-turn will be easier to coax out of him/her. Having them watch videos on you-tube might help as well; you can go through the mechanics slow-mo. I've been doing flip turns less than a month now and they're already starting to feel a lot smoother, more natural.

If it's pre-competitive anyway... why not give the option of open turns; and coach them on an effective open turn? I did open turns for years and just taught myself flip turns because I've only started taking my swimming seriously in the last couple of years. As the student becomes a stronger swimmer and wants to swim competitively, the flip-turn will be easier to coax out of him/her. I think this is important. I learned to swim as a kid, but never took it seriously until I was in my 20s. I learned flip turns when I was 22. For a while I really wanted to do it, I expended way too much energy thinking about it, would see little kids doing them effortlessly, and it all just frustrated me. I took a break from those, learned/cleaned up the other strokes, and the flip turns just kind of happened when I wasn't trying so hard. Maybe just skim over flip turns for now, and revisit them every now and then.

I had great turns in high school when I never thought about what I was doing, and the more I think about the mechanics since I returned to swimming, the worse they get :)

You don't say how old the swimmer is. Since there is a problem completing the flip, it may not be mechanics, but age or negative experience in the past. I had a brother in law that I could not teach to dive into the pool, found out later that he wore a scuba mask in the shower. You might have a conversation with the swimmer and find out how he feels about the experience of swimming overall. Once he knows you are listening, he may try new things (like a flip turn) without any resistance, either overt or subliminal.

Does he/you try to use the hands ,palms down , at the hips as the head drops & pull hard ,up & to the face to aid in the flip moon?

So I have recently over a period of time gone through the process of learning flip turns. Here is my experience. I can do an open turn just as fast as a flip turn. Really. I get a better underwater push off the wall with a good flip turn though. For a long time I did not want to do flip turns and lose that breath. I also have to breath out during the turn and had a fear of running out of air. It's true. I started doing flip turns when doing kick drills on back with fins. This gets you around a lot quicker. There is therefore an incentive and less worry about having enough air. I started out just practicing a somersault in the middle of the pool, just to turn over, with arms out to the side, and stay straight. It's OK to do this at the wall. Whatever works. I gradually incorporated more flip turns as I felt good about it. Sometimes if I am late, or off time breathing, it is just easier to do an open turn. No problem, see 1. After some practice and getting comfortable with it, say work up to an 800 with all flip turns. Then refinements help. The flip turn article in Swimmer magazine helped. Thinking about flipping straight over instead of sideways helps. Do flip turns on backstroke and then add to freestyle. In the end, there are lots of ways to get around and good form just comes with practice and a little knowledge.