Contesting a real property deed
I want to contest the validity of a Virginia deed adding my sister as joint tenant w/ survivorship rts to a deed with my mother which purports to bear my mother's signature . On the date of the deed my mother was comatose and unable to sign or understand anything and she died soon after. She had always spoken of my having this property with my sister having another piece of property after her death. My sister now claims both properties. Do I contest through probate court or some other court . How do I do it? Will testimony from a VA Dr. who treated my Mom that says she was mentally unable to understand business transactions at that time, help ? Thank you