Law student here. I think I have to agree. CA 473 is the relevant law on naturalization, I think.
Sec. 15, CA 473. Effect of the naturalization on wife and children. - Any woman who is now or may hereafter be married to a citizen of the Philippines, and who might herself .be lawfully naturalized shall be deemed a citizen of the Philippines.
Minor children of persons naturalized under this law who have been born in-the Philippines shall be considered citizens thereof.
A foreign-born minor child, if dwelling in the Philippines at the time of the naturalization of the parent, shall automatically become a Philippine citizen, and a foreign-born minor child, who is not in the Philippines at the time the parent is naturalized, shall be deemed a Philippine citizen only during his minority, unless he begins to reside permanently in the Philippines when still a minor, in which case, he will continue to be a Philippine citizen even after becoming of age.
A child born outside of the Philippines after, the naturalization of his parent, shall be considered a Philippine citizen, unless within one year after reaching the age of majority, he. fails to register himself as a Philippine citizen at the American Consulate of the country where he resides, and to take the necessary oath of allegiance.
So, based on the underlined portions, Brownlee Jr. is also naturalized thanks to JB's naturalization. He's 11, right? That's minor age, meaning either way he's also a naturalized citizen. If he was in the Philippines at the time JB was naturalized, he's automatically a Filipino citizen for life. If he was abroad at the time, he's only a Filipino citizen until 18, unless he resides here permanently.
By the way, ja.he is already a lawyer. He passed the bar last year.