YOU SAID:

she was ill when she went to her brother's best friend's dads graduation party

INTO JAPANESE

兄の親友の父親の卒業パーティーに行ったとき、彼女は病気だった

BACK INTO ENGLISH

She was sick when she went to her brother's best friend's father's graduation party.

INTO JAPANESE

兄の親友の父親の卒業パーティーに行ったとき、彼女は体調が悪かった。

BACK INTO ENGLISH

She was not feeling well when she went to her brother's best friend's father's graduation party.

INTO JAPANESE

兄の親友の父親の卒業パーティーに行ったとき、彼女は体調が優れませんでした。

BACK INTO ENGLISH

She wasn't feeling well when she went to her brother's best friend's father's graduation party.

INTO JAPANESE

兄の親友の父親の卒業パーティーに行ったとき、彼女は気分が優れませんでした。

BACK INTO ENGLISH

She wasn't feeling well when she went to her brother's best friend's father's graduation party.