(a) Except as provided by Subsection (b), in a proceeding brought under Section 123.102, the court shall declare the decedent's marriage void if the court finds that, on the date the marriage occurred, the decedent did not have the mental capacity to:
(1) consent to the marriage; and
(2) understand the nature of the marriage ceremony, if a ceremony occurred.
(b) A court that makes a finding described by Subsection (a) may not declare the decedent's marriage void if the court finds that, after the date the marriage occurred, the decedent:
(1) gained the mental capacity to recognize the marriage relationship; and
(2) did recognize the marriage relationship.