What does it mean that his life is uncertain?

Meaning: The next life is unpredictable, so this life is over.

This sentence comes from "Mawei" by Li Shangyin of the Tang Dynasty

Mawei (Part 2)

The author Li Shangyin? Dynasty Tang

Translation comparison

Overseas disciples heard about Jiuzhou, and their fate was uncertain.

In the sky, I heard that the tiger travels to announce the night watchman, but there is no more chicken man to announce the dawn.

On this day, the six armies were stationed together, and the Chinese Valentine's Day laughed and morning glory.

How can the Four Ji be the emperor, not as good as the Lu family?

Translation:

I heard the legend in vain that there are Kyushu overseas, and the next life is unpredictable, so this life is over. In the sky, I heard the Imperial Guards fighting and fighting with swords at night. There were no more chicken men in the palace. The dawn was announced and the beatings were even better. The six armies have agreed to stop moving forward. I recall that on Chinese Valentine's Day, we laughed at the Weaver Girl plowing cattle. How come after four centuries, he was the emperor, but not as good as the husband-in-law of the Lu family. He stayed with Mochou day and night. Extended information

This is a political satire poem, directed at Tang Xuanzong, the former emperor of Li Tang Dynasty. ?

Overseas disciples heard about Jiuzhou: This is used in Bai Juyi's "Song of Everlasting Sorrow" to mean "suddenly heard that there are fairy mountains overseas", referring to the fact that Yang Guifei lived in fairy mountains overseas after her death. Although she heard the news that the Tang Dynasty restored Jiuzhou, But humans and gods are separated, and they can no longer reunite with Xuanzong. "Merely heard", empty hearing, unfounded hearing. "More", again, and more. "Jiuzhou", the original annotation of this poem: "Zou Yanyun: Beyond Jiuzhou, there are Jiuzhou."

During the Warring States Period, Zou Yan, a native of Qi, created the theory of "Nine States", saying that China was named Chixian Shenzhou, China In addition, there are nine other places as big as Chixian Shenzhou. This poem uses "overseas nine states" to refer to the imaginary wonderland. After Yang Guifei died, some alchemists said that she could be found in the fairy mountains overseas. See Bai Juyi's "Song of Everlasting Sorrow" and Chen Hong's "Song of Everlasting Sorrow". But after all, the legend of gods and immortals is vague and cannot give any comfort to Emperor Xuanzong of the Tang Dynasty, so it is said to be "just heard".

His life is uncertain: Chen Hong's "The Song of Everlasting Regret": Tang Xuanzong and Yang Guifei once said in the middle of the night of Chinese Valentine's Day, "we secretly vowed to each other, wishing to be husband and wife for the rest of our lives, holding hands and sobbing." But what about the afterlife? It is still unknown, but the couple in this life is already finished.

Reference: Baidu Encyclopedia - Mawei’s Two Poems