hi in the lesson there is

Question

Accepted Answer

Hi,
 Il déteste son frère 
means  
He hates his/her brother
so in French, you will need more context to know who the 'son' refers to.
Elle déteste son frère
will be
She hates his/her brother 
same thing.
Hope this helps!

Answer

Il déteste son frère.
He hates his brother.

but how would you change this to be the french for he hates HER brother

Answer

Rona, The sentence would be Elle déteste son frère. The elle would indicate her. SON won't change.

Answer

Are you sure Son doesn't change to Sa as you are describing gender possessive,  and the brother being the possessive to the Female makes Sa?

Answer

"son" agree with the gender of the noun "frère". So it's right to say "Elle déteste son frère."

Answer

He hates her brother. The subject is he, il. the object is 'her brother'. brother is masculine, so would be 'son frère'. So if I understand rightly, He hates her brother would be Il déteste son frère.

Answer

That's a good question.

Answer

Il déteste le frère de _________. (He hates the brother of __________)

Answer

This is a very good question, which I think the lesson should address.

My understanding is that whilst, grammatically, «Il déteste son frère» could be someone else's brother, in practice it would be understood as "He hates his brother" unless you have surrounding context to the contrary.

If you need to clearly refer to someone else's brother then you have to use a structure like the one Dawn suggests, with either à or de. If it's a (stress) pronoun, then you need to use 'à', if it's a name or noun, then you need to use 'de': https://www.thoughtco.com/french-possession-1368906