(1) In an action to contest the validity or revocation of all or part of a trust, the contestant has the burden of establishing the grounds for invalidity.
(2) An action to contest the validity of all or part of a revocable trust, or the revocation of part of a revocable trust, may not be commenced until the trust becomes irrevocable by its terms or by the settlor’s death. If all of a revocable trust has been revoked, an action to contest the revocation may not be commenced until after the settlor’s death. This section does not prohibit such action by the guardian of the property of an incapacitated settlor.