YOU SAID:

my cousin's husband's mother works in my mother's brother's wife's store

INTO JAPANESE

私のいとこの夫の母親は私の母の兄の妻の店で働く

BACK INTO ENGLISH

My cousin's husband's mother works in the store of my mother's brother's wife

INTO JAPANESE

私のいとこの夫の母は私の母の兄の妻の店で働いています

BACK INTO ENGLISH

My cousin's husband's mother works in the store of my mother's brother's wife