Section 20. The custodian shall transfer in an appropriate manner the custodial property to the minor or to the minor’s estate upon the earlier of:

(1) the minor’s attainment of twenty-one years of age with respect to custodial property transferred to a custodian nominated as provided in section three or transferred under section four or section five;

(2) the minor’s attainment of majority under the laws of the commonwealth, other than this chapter, with respect to custodial property transferred under (i) section six; or (ii) section seven, except in the case of a transfer to a custodian nominated as provided in section three; or

(3) the minor’s death.