In the 60’s ‘black’ or ‘negro’ would have been the most widely used description for race.
No one would put ‘American’ as ‘Race’ for an American citizen anymore than they would put ‘African’ for a citizen of an African country.
Obama’s father being from Africa doesn’t mean he is ‘African’.
His ‘race’ would probably depend upon which part of Africa he was from.
If he came from an Arab nation, then ‘Arab’ would probably be the correct word.
What ‘race’ is a person from Kenya?
Sure isn’t ‘African’.
“In any case, the use of “African” to describe his father still seems strange.”
I agree.
Strangely enough, in Kenya that depends on religion. Muslims of the Luo tribe (Obama's tribe) call themselves "Arab."