Sec. 309. [8 U.S.C. 1409]
(c) Notwithstanding the provision of subsection (a) of this section, a person born, after December 23, 1952, outside the United States and out of wedlock shall be held to have acquired at birth the nationality status of his mother, if the mother had the nationality of the United States at the time of such person's birth, and if the mother had previously been physically present in the United States or one of its outlying possessions for a continuous period of one year
OK now the question is, was the marriage of 0’s dad to the Kenyan lady one that would be recognized as valid in the u.s. If it was just a tribal marriage and not legally recorded, then maybe there would not be a problem of bigamy, and the “in wedlock” would apply, since supposedly his mom and 0 SR got married in Hawaii. So this case pegs him as non NBC.
If there was a bigamy problem, and it was “out of wedlock”, then another question related to your law qoute would be, was his mom in the u.s. for a year prior to the birth...
If she left the us right after marrying 0 SR then 0 wouldn’t be NBC... she would’ve been here maybe eight months or so.