Tex. Est. Code § 55.101

Notwithstanding Subtitle B, Title 3, Occupations Code, a person who is a party to a will contest or proceeding in which a party relies on the mental or testamentary capacity of a decedent before the decedent's death as part of the party's claim or defense is entitled to production of all communications or records relevant to the decedent's condition before the decedent's death.