It would be ton frere(informal) or votre frere(formal). It doesn't matter whether its a girl or boy saying it.
"my brother and me" in French is "mon frère et moi"
Allemand (german boy) Allemande (german girl)
You would say "Je t'aime mon frère" in French to express "I love my brother."
demi frere
J'aimerais un frère
If you are also a boy, you would say "kaikaina" for a younger brother (kaikua'ana for an older brother). If you are a girl, you would say "kaikunane" for a brother.
"Brother from another mother" in French would be "frère d'une autre mère."
You can say "mon frère" to mean "my brother" in French.
où est ton frère ?
You would say "Je n'ai pas de frère" in French to express "I don't have a brother."
You would write 'Big Brother' as 'grand frère' and pronounce it as grand frer
In French, the word for "the brother" is "le frère."