Section 6. Property held in trust under the provisions of subclause (iii) of clause (2) of subsection (a) of section five shall be held upon the following terms:

(1) During the life of the surviving spouse, the entire net income shall be paid to or for the benefit of the surviving spouse in quarterly or more frequent installments. Net income accrued or undistributed on the death of the surviving spouse shall be paid to the estate of the spouse. If unproductive property is held in the trust, the surviving spouse at any time by written instrument delivered to the trustee may compel conversion of the unproductive property to productive property.

(2) During the life of the surviving spouse, the trustee at any time may pay to or for the benefit of the surviving spouse and issue of the testator amounts of the principal the trustee deems advisable, giving reasonable consideration to other resources available to the distributee, for the individual's needs for health, education, support, or maintenance. For the purpose of making such discretionary payments, the principal shall be administered as two separate shares, which at the inception of the trust shall be equal. One share is the surviving spouse's share of the principal. During the life of the surviving spouse, payments may not be made from the surviving spouse's share to anyone other than the surviving spouse. Primary consideration shall be given to the needs of the surviving spouse and the children of the testator who are under the age of twenty-three years or under disability. The trustee may rely in good faith on a written statement furnished by a beneficiary. The discretion to pay principal to or for the benefit of any individual includes the discretion after that individual's death to pay expenses incurred before the individual's death and to pay funeral and burial expenses. If the trustee, other than the surviving spouse, determines that continuation of the trust is uneconomical, the trustee may terminate the trust by distribution of principal to the surviving spouse. Principal that in the exercise of the trustee's discretion is paid to or for the benefit of any issue may be charged against any share of income or principal thereafter existing for that issue or for any ancestor or descendant of that issue, if the trustee upon equitable considerations so determines. If the surviving spouse or any issue is serving as trustee, the trustee's discretion pursuant to this paragraph is not exercisable in favor of that trustee except as necessary for the trustee's needs for health, education, support, or maintenance, nor is the trustee's discretion exercisable in favor of the trustee's estate, the trustee's creditors, or creditors of the trustee's estate.

(3) On the death of the surviving spouse, the principal, unless retained in trust under the provisions of section eight or nine, shall be paid, subject to any charges made by the trustee under the provisions of subparagraph (2), to the children of the testator in equal shares if all of the children are then living, otherwise to the then living issue of the testator by representation or, if no issue of the testator is then living, to the individuals who would be entitled to receive the estate as if the property were located in the commonwealth and the testator had then died intestate domiciled in the commonwealth in proportions determined under the law then existing.