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?