Like Vitamin K having a role in Vitamin D enabling Calcium to be absorbed - and fat in the diet being necessary for both Vitamin D and Vitamin K to function. Or excess salt in the diet resulting in Calcium being pulled from the bones (I'm drowning a bit in calcium related things as I recently found out I have osteoporosis quite a bit worse than "normal" - if there is such a thing.)
My VERY sincere condolences. Yes, there is such a thing. My wife suffers. Hope it was diagnosed early and you can enact some dietary steps to slow progression. We are dreading her next bone density scan.