demi-frère
Has two brothers in French is 'a deux frères'. This could be used in a sentence, for example, to say 'She has two brothers': 'Elle a deux frères'.
You would say "J'ai quatre frères" in French to mean "I have four brothers."
One half in French would be demi.
To say "your brothers are twins" in French, you would say "Tes frères sont jumeaux."
My other two brothers in French is 'Mes deux autres frères'.
J'ai trois frères
my brothers -- mes frères -- "may frehr"
He has no brothers. -> Il n'a pas de frères. "eel nah pah d(uh) frehr"
J'ai huit frères
"une demi-soeur"
et demi
trois frères