There is this simple sentence I don't quite understand, grammatically;
Он думает, ты знаешь его брата.
He thinks you know his brother.
So based on things like,
Ivan's dog = The dog of Ivan
собака Ивана (nominative, genitive)
I understand that его is genitive (he 'owns' the 'him/brother'; in fact the possessive of он is его) and брата would be the object of 'to know', and hence accusative.
I guess I would write it as (but probably not standard?);
Он думает, ты знаешь брата его.
I just want to check these case roles because masc. animate nouns have the same spelling in genitive and accusative cases (minus minority endings).
Also, его can be a possessive pronoun (genitive of он) or the accusative.
So, my question is:
Is my assumption correct, that его is in the genitive and брата is in the accusative?