Get her Vitamin D checked with a blood test. Depending on her results she might need prescription strength vitamin D. Even if she does not take a scrpt she will monitor her vitamin D level and calcium levels. The US recommended amount of D is 400iu’s a day. I was taking 50,000 iu’s a week, finally got my D up into normal ranges, and then my doctor and I decided to switch to over the counter to maintain the levels. My numbers went down down down. I was taking 2,000 iu’s a day, and it was not close to what I obviously need.
Also, vitmamin K is very important along with D to get the calcium into the bone. See, if the calcium level in the blood stream is too high it can indicate that calcium is settling in arteries and other soft tissues and organs, which is bad for us, it stiffens tissues, and creates plaque in arteries.