Act quickly, especially since you have the hunch that not all is on the up and up.
But first try to resolve your problem within the nursing facility. It should
have written policies readily available that explain how to file a complaint or grievance. Put complaints in writing to the facility administrator and ask for a written response -- giving him or her a fair chance to address your concerns.
If that doesn't give you satisfaction, contact the facility's ombudsman. An ombudsman is a person outside the facility, not associated with the ownership, who is trained to investigate problems and endeavors to resolve complaints made by, or on behalf of, residents in residential care facilities. You can find the local one at http://www.nursinghomealert.com/ombudsman.html.
Finally, if that fails, too, there are a number of local organizations that can offer you a seasoned and impartial assessment of whether your particular complaint needs additional action, along with specific help on how to get it. You should be able to find local sources through the National Senior Legal Hotline Directory at http://www.proseniors.org/National_Hotline_List.html.