YOU SAID:
Brother from another mother.
INTO JAPANESE
母親が違うだけだろ?
BACK INTO ENGLISH
Is not it just a different mother?
INTO JAPANESE
それは別の母親だけではありませんか?
BACK INTO ENGLISH
Is not that just another mother?
INTO JAPANESE
それだけで別の母親ではないですか?
BACK INTO ENGLISH
Is not that just another mother?
That didn't even make that much sense in English.