его матери

his mother

→ он
phrase Rare #40,074
his mother The form матери changes according to the grammatical case: it can mean “of his mother,” “about his mother,” or “to his mother,” depending on the sentence. Его means “his” and does not change form.
RU: Я часто звоню его матери.
EN: I often call his mother.

Он мог существовать исключительно в воображении его матери.

He could have existed solely in his mother's imagination.

— Во время грозы (2018)

Позвони его матери.

Call his mother.

— Плата за страх (1953)

Его матери, которая готовила еду мне и своему сыну.

His mother, who cooked food for me and her son.

— Ветер, который качает вереск (2006)

Пойти успокоить друга или вытереть слезы его матери.

Go comfort my friend or wipe away his mother’s tears.

— Три идиота (2009)

О его матери?

About his mother?

— Кто я (2014)