A trustee is the proper plaintiff to sue to enforce a right of the trust estate, except that a beneficiary may sue to enforce such a right, in order to protect his own interest, in an action against:
(1) A trustee and an obligor, if the trustee improperly refuses, neglects, or is unable for any reason, to bring an action against the obligor; or
(2) An obligor, if there is no trustee or the trustee cannot be subjected to the jurisdiction of the proper court.