(a) The right of election may be exercised only by a surviving spouse who is living when the petition for the elective share is filed in the court under subsection (a), section four of this article. If the election is not exercised by the surviving spouse personally, it may be exercised on the surviving spouse's behalf by his or her conservator, guardian, or agent under the authority of a power of attorney.

(b) If the election is exercised on behalf of a surviving spouse who is an incapacitated person, the court must set aside that portion of the elective-share and supplemental elective-share amounts due from the decedent's probate estate and recipients of the decedent's reclaimable estate under subsections (b) and (c), section six of this article and must appoint a trustee to administer that property for the support of the surviving spouse. For the purposes of this subsection, an election on behalf of a surviving spouse by an agent under a durable power of attorney is presumed to be on behalf of a surviving spouse who is an incapacitated person. The trustee must administer the trust in accordance with the following terms and such additional terms as the court determines appropriate:

(1) Expenditures of income and principal may be made in the manner, when, and to the extent that the trustee determines suitable and proper for the surviving spouse's support, without court order but with regard to other support, income, and property of the surviving spouse and benefits of medical or other forms of assistance from any state or federal government or governmental agency for which the surviving spouse must qualify on the basis of need;

(2) During the surviving spouse's incapacity, neither the surviving spouse nor anyone acting on behalf of the surviving spouse has a power to terminate the trust; but if the surviving spouse regains capacity, the surviving spouse then acquires the power to terminate the trust and acquire full ownership of the trust property free of trust, by delivering to the trustee a writing signed by the surviving spouse declaring the termination;

(3) Upon the surviving spouse's death, the trustee shall transfer the unexpended trust property under the residuary clause, if any, of the will of the predeceased spouse against whom the elective share was taken, as if that predeceased spouse died immediately after the surviving spouse, or, if there was no residuary clause or no will of that predeceased spouse, to the persons and in such shares as would succeed to that predeceased spouse's intestate estate as if that predeceased spouse died immediately after the surviving spouse.