Haw. Rev. Stat. § 554B-10
(a) A beneficiary is incapacitated for the purposes of this chapter and the custodial trustee shall administer and distribute the custodial trust as one for an incapacitated beneficiary:
(b) A custodial trustee may determine that the beneficiary has become incapacitated in reliance upon:
[L 1989, c 76, pt of §1]