I have a student who is struggling with flipturns!

So I've been a pre-competitive swim coach since May now. I love it! However, I have a student in one of my lower level classes who is really struggling with learning flipturns. No matter what I suggest or what approach I take, class after class, he is rarely able to progress to doing half of a somersault, let alone a full somersault (which he has never done). I tell him to tuck his chin on his chest, keep his head straight, hands and arms at his side, legs up to chest in cannon ball, but no matter what, he really struggles to get his head and upper chest down away from the surface of the water, and then his legs straighten out behind him and it's all over. Swinging kickboards out to his side as he initiates the maneuver has rarely helped. What are your suggestions? I am stumped. :sad: