I also have to take short strides, I have hypermobile joints. Can she bend her fingers backwards? If so, it's likely that she has hypermobility and a wider stride would allow her joints to slide around and cause serious damage. This is genetic. The connective tissues are just mushier. Short strides are the cure if running is a must. If she is hypermobile, definitely advise against stretching her leg muscles, they need to be taut to help stabilize.
Steak, eggs, potatoes - fruits, nuts, berries and forage. Coconut milk and potent herbs and spices. Tea instead of coffee now and teeny amounts of kelp daily. Let's see how this does! Not really had dairy much, and gut seems better for it.