depakote and osteoporosis

My son has been on Depakote since he was 8 yrs old. He is now 23. He has always had blood work done but never a bone density test. Now I am reading a lot about osteoporosis and am worried. He has never taken any vitamin d or calcium supplements. I found a good product online called osteomd by 1MD but I am afraid of having him take it because there is an ingredient called cisscus guadrangularis. Anyone heard of it? is it safe? or should I just stick to a regular vitamin D and Calcium multi. Also should I ask for a bone density test or do you feel as long as his vitamin d levels have been ok up to this point I should assume he is ok.