His erstwhile friends turned against him.

他先前的朋友转而与他作对。

《牛津词典》

The tide turned against him.

形势变得对他不利。

youdao

As the old ruling circle has turned against him, even threatening him with imprisonment, he has boldly refused to bow out.

不过尽管旧统治体系与他敌对，甚至威胁要对他实行监禁，但是他勇敢的拒绝了退出。

youdao

But in the end, once Nixon's dirty tricksters started to be indicted, the public turned against him.

ECONOMIST: How long will they love him?

Brown's political fate was finally sealed when two groups that he had most favoured, students and blacks, turned against him.

ECONOMIST: American politics

Two years after backing the Conservatives in Britain, Murdoch now rails against the government that turned against him over phone-hacking.

CNN: Rupert's Twitter feed: 10 lessons from Planet Murdoch