My mother in-law is in a nursing home in zwolle, LA and got a broken leg in 2 places, yet no one knows what happened, or they're not telling. What should I do?

That is strange. If she fell out of bed or something, someone should know. However, if she has osteoporosis - not uncommon in elderly women - a bone can spontaneously break, causing another fracture in the process. Still, they should be investigating and not brushing you off. If you don't think they are cooperating, contact the ombudsman for that area (www.ltcombudsman.org). They can advise you.
Good luck,
Carol