Could be he is twisting the bow when he draws, either right hand or left, will the throw the bow off track. The only thing that would cause this, other than physical pressure, would be exposure to extreme temps. I have bows that have been in use for 60 years and have only had one break and that was another person twisting on it. This fellow needs a reverse handled Howard Hill Tembo or Big Five, with a straight grip, 64" to more than match his 26" draw, and pay close attention to getting the bow into the hand without torquing and make certain that the release fingers are equal pressure on the string during the straight back part of the draw with a split finger standard draw. He says he is trying to use Hill form, it works best with a Hill bow. i have been known to torque up a grip on recurves shooting Hill style to the point of lifting the arrow off the shelf.