http://www.unhcr.org/refworld/docid/3ae6b4ec8.html
Article 7.
(2)With the exception as mentioned in para 1 the foreign woman who marries a citizen of the Republic of Indonesia also acquires the citizenship of the Republic of Indonesia one year after the marriage has been contracted , if within that one year her husband does not make a statement as to release his citizenship of the Republic of Indonesia.
Since Lolo did not renounce his citizenship SAD, in the eyes of Indonesia, became an Indonesian citizen in March 1966. This is automatic.
Another link that shows that this is an automatic action.
http://www.expat.or.id/info/familylaw.html
"If the foreign wife has not made such declaration to opt, she will nevertheless acquire Indonesian nationality after the first year of marriage, provided that the Indonesian husband has not in the meantime renounced his nationality. "
So how does the entire family become Indonesian citizens but the child not? It fails every logic test.
In all likelihood Obama was a legal, 100% Indonesian citizen - until 1971.
What does Indonesian law say about the children of the foreign lady?
And what does u.s. law say about people that go to other countries and fill out citizenship apps or automatically become citizens of that country?
Probably it lets them do it, see the FAM posts I put up.
But the FAM documents don’t allow change of citizenship if child is younger than 16.
So I guess whatever citizenship 0 originally had, he kept.
And maybe also somehow got Indonesian along the way.