Will I lose my house to medi-cal estate recovery program?

My father in law helped us to purchase a house. The deeds were named to my wife and to my father in law on a Joint Tenancy title. My father in law didn't put money on it we just use his name for credit check history I can produce all the papers that all the monies came from our acct. and I even took some money from my 401k( downpayments ,deposit & home improvements). My father in law was a medi-cal benefitceary . We receive a letter from medi-cal estate recovery that they are going claim against the property. What options do we have to avoid the claim? Please help. Thank you.