YOU SAID:

i had a party at my brothers house

INTO JAPANESE

私は兄弟の家でパーティーをしました

BACK INTO ENGLISH

I had a party at my brother's house

INTO JAPANESE

兄の家でパーティーをしました

BACK INTO ENGLISH

We had a party at my brother's house

INTO JAPANESE

兄の家でパーティーをしました

BACK INTO ENGLISH

We had a party at my brother's house