You can try a FOIL (Freedom of Information Law) request.
The above answer, and any follow up comments or emails is for informational purposes only and not meant as legal advice.
You probably don't. I'm just guessing here, but I bet the records for a 15 year old closed case have been discarded. Medicare is administered by US. Dept of Health and Human Services Centers for Medicare and Medicaid services. Medicaid fraud would be handled by a state or local agency.
Suppose you somehow can get the records. How will they help you? It's probably too late to get remedies for any alleged wrongs at this point. Besides do you really want to blow up the family over an incident 15 years ago that may not even involve wrongdoing?
Lawrence Friedman, Bridgewater, NJ. Certified as an Elder Law Attorney by the ABA approved National Elder Law Foundation, former Chair NJ State Bar Association Elder and Disabilities Law Section, Member Board of Consultors of NJSBA Real Property, Trusts & Estates Law Section, Vice Chair Special Needs Law Section of National Academy of Elder Law Attorneys, and Master of Laws (LL.M.) in Taxation from N.Y.U. School of Law. Visit SpecialNeedsNJ.com for articles and Q&A on elder law, special needs, wills, trusts, estates, and tax. Visit SpecialNeedsNJ.com/blog and subscribe for free timely updates to be delivered to your inbox. Information on both Avvo and SpecialNeedsNJ.com does not constitute legal advice, as it is general in nature and may not apply to your situation or be subject to important changes. No attorney client relationship exists unless set forth in written engagement terms.
I had a somewhat similar case and I wrote to the Office of the Attorney General or District Attorney who had handled the matter and that office shared contents of the file with me as the attorney for the elderly individual who had been the subject of the alleged fraud or abuse (and who by the time of my inquiry had died). I suggest that you have your attorney attempt to contact the Attorneys in the Medicaid Fraud and Abuse Office. You can also attempt to us the New York Freedom of Information Law (F.O.I.L.) to seek information. They may refuse, however, to release any grand jury minutes or proceedings but may allow access to other materials in their files. You may have a statute of limitations (passage of time) problem with any possible claim. Consult with an attorney immediately.
This answer does not constitute legal advice in any form ; you have to meet and consult with an attorney on this matter.