Haw. Rev. Stat. § 432:1-622: Extension of dependent coverage.

Each individual or group hospital or medical service plan contract and each mutual benefit society offering individual or group hospital or medical service plan contracts that provide dependent coverage of children shall continue to make that coverage available for an adult child until the child turns twenty-six years of age. Nothing in this section shall require a plan contract to make coverage available for a child of a child receiving dependent coverage.