his, her, your, or their older sister
Mary hacía como que era su hermana mayor.
Mary pretended to be her older sister.
Ella no es menos encantadora que su hermana mayor.
She is no less charming than her older sister.
Su hermana mayor se casó el mes pasado.
Her older sister got married last month.
Kazuko se parece mucho a su hermana mayor.
Kazuko looks a lot like her older sister.
¿Cómo se llama su hermana mayor?
What’s his older sister’s name?
Mary hizo como que era su hermana mayor.
Mary pretended to be her older sister.
Mary fingía ser su hermana mayor.
Mary pretended to be her older sister.
Ella no es menos bonita que su hermana mayor.
She is no less beautiful than her older sister.
Entonces eres su hermana mayor, ¿cierto?
So you're her older sister, right?
— El tiempo contigo (2019)
Ella no es tan bella como su hermana mayor.
She is not as beautiful as her older sister.