My friend's sister is man.

Wouldn't that make him a brother?

HShe lives far hisfrom her family.

my question is: why you wrote she lives...
I mean: He lives...not she. because a friend's sister is man not woman.

No - a sister is a woman/girl, not a man.

https://www.merriam-webster.com/dictionary/sister
https://dictionary.cambridge.org/dictionary/english/sister
https://www.dictionary.com/browse/sister
https://www.collinsdictionary.com/dictionary/english/sister

Hi Diggn,

Firstly, thank you for your attention and reply.

Please read my text:

My friend's sister fast every Thursday. He lives far his family. That's way I cooked a

delicious food for him.

My explacation: My sister has a friend (man) not woman. ok.
That's why, i began my sentence with:
My sister's friend.ok

Who is fatsting? OK
Man fasting every Thursday. not my sister(woman)
So I said: My sister's friend fasting evrey Thursday...ect

I said also: He lives far his family. I put He not she because I spoke always (man) my sister's friend.

I hope my explication is clear.
Thank you very much.

In that case the sentence needs to be "my sister's friend" ... you've mixed up the direct and indirect object. As you wrote it your friend (of an unknown gender) has a sister (definitely female) who you were cooking for.
You explanation if fine, your grammar was off.

Oh my God!!

I will post this topic in other day...because I didn't understand it.

Thank you a lot.

You're welcome. :)