problems with an estate in VA

To Whom It May Concern:

I need some legal advice at this time regarding my late father's estate. In 1998, my father made a living trust in NY. To my knowledge, it was filed in the county clerk's office. After my father became very ill, he resided with my sister in VA. He had been diagnosed with Dementia and Lymphoma as well as other significant medical problems from 2001-2003. My father passed away in Oct., 2005. At this time, I found out that my father supposedly had changed his will in August, 2003, about the time that he was give little chance to live. Before the Circuit Court in Fairfax County, VA is an unsigned will and an alleged letter written by my father to an attorney's office with his new intentions to make a new will. I know that my father could not have written or typed the letter due to his diminished physical and cognitive functioning. His signature was never witnessed or dated. The lawyer's office never stamped it as to the date of receipt. It is my understanding that a legal will needs to be signed. Interestingly enough, he lived three years after the will was drawn up and he never signed it. There is not much money in the estate, and I don't have alot of money. Is an unsigned will and a letter of intention without a witness to my father's signature legal in VA? Thank you for your assistance.