First of all, when a person dies the family has one year from the date of death to open an estate in probate court. It would appear from the information that you provided that it is too late to open such an estate. If there remain questions as to whom is entitled to receive certain assets from the estate the only procedure left is one that is called "Determination of Heirship." With respect to the statute of limitations, it depends on what kind of a debt your father owed to your sister. On contracts for the payment of money these would normally be evidenced by a promissory note to the order of your sister, dated and signed by your father. This type of obligation would have a statute of limitations of 10 years. As to the calculation of the 10 year period a lot may have to do with what happened from the time the note was signed until the time of your father's death. If no such evidence of indebtedness exists the statute of limitations would, in all probability, be five years. Based on the information that you provided it would seem that there was no evidence of this debt. If your sister hopes to recover this she would have to hire counsel and initiate an action to determine heirship. As I mentioned she would have to retain counsel and then provide evidence to prove her claim. If an issue arises with respect to the authenticity of the checks she has produced she may have to hire an expert to prove their authenticity. By the same token, you may have to hire your own expert to prove that these documents are not authentic. My guess would be that this litigation could take a considerable amount of time.
Answered on Dec 31st, 2013 at 4:58 AM