It is negative. His long-lost son is not his son after all.

结果是消极的，他那多年失散的儿子根本就不是他的儿子。

youdao

An old pandit exile, who had been such a close friend of Mr Peer's father that she greets the young man as a lost son.

一位年长的流亡梵学家、皮尔父亲曾经的密友，欢迎皮尔这位年轻人的回来，就像是在欢迎失去的儿子。

youdao

They areconstantly reminded of their lost son, the oldest of three children, often withlaughter, at times with shared tears.

他们时常想起这个失去的儿子，他是三个孩子中的老大。

youdao

His son Teddy lost his leg to cancer at the age of twelve in nineteen seventy-three.

VOA: special.2009.09.13

If my advice is lost in the wind and you do not do as I wish, I do not recognize you as my son."

如果你辜负了我对你的期望,胆敢把我的话当耳边风,我就绝不认你这个儿子"

耶鲁公开课 - 欧洲文明课程节选

He told the president that he had lost a son in the fighting at Gettysburg.

VOA: special.2009.11.12

His return to London in 2009 was celebrated like the return of a long lost son.

FORBES: A French Chef Looks To Break The Rules And Change The World With New Restaurant

Years later, Philomena goes to the U.S. to search for her lost son, who has become a lawyer and Republican politician.

WSJ: Starring Your Den

Reg Keys, who lost his son Tom, said their deaths had been caused by negligence.

BBC: NEWS | UK | Criticism over Red Caps' deaths