He is Mary? S younger brother.

他是玛丽的弟弟。

youdao

Muller's father managed to buy her freedom and that of her younger brother.

VOA: standard.2010.04.10

Milton's younger brother, Christopher, was already entering law school at this time, and it was clear, I guess, to everybody that John Milton, Jr. was not suited why that's the case.

弥尔顿的弟弟，克里斯多夫，在这时已经进入了法学院，我猜想，弥尔顿并不适合,我不清楚为什么）

耶鲁公开课 - 弥尔顿课程节选

Let's say that you're talking to your younger brother and sister.

假设你正在和弟弟妹妹说话。

It's important 课堂 - SpeakingMax英语口语达人

Foer's younger brother Joshua told him it sounded like he was writing about September 11.

CNN: The Foer questions: Literary wunderkind turns 35

Of the other possible candidates, the most intriguing is Ed Miliband, David's younger brother.

ECONOMIST: Labour's future

"We don't deserve this kind of treatment, " said Mr Sodhi's younger brother Latwinder Singh Sodhi.

BBC: Sikh protestors