I have had major urinary frequency problems my entire life.
I just started taking MSM a few weeks ago, but don't know if it is helping, i guess i will give it few more weeks. Maybe if it seems to be helping your sister, you could let us know for sure in another few weeks, to see if that is what it really is, that is helping her.
I just started taking alfalfa tablets a few days ago. They are also supposed to be good for kidneys/bladder and many other things, so i will let you know in a few weeks if infact the MSM and alfalfa are helping me out.