Son, read the answer.

Two years ago, Zi died at the border. On that day every year, the old man cooks several dishes, puts them in the direction of Yunnan and sprinkles several glasses of wine. The son loved to drink before his death, but the old man didn't cry. This is a typical Dashan character: perseverance and perseverance.

In the past two years, I have received monthly remittance from 20 yuan, Yunnan Frontier Defense. At first, there was only remittance. Later, the old man couldn't help it, and asked his neighbor Xiaogang to write a letter for him to this comrade who called himself "Xie Weimin". "Xie Weimin" read the letter and knew that the biggest difficulty for the old man was loneliness, so the old man received another letter every month. Be caring and attentive, and talked about the life of the army and my marriage. Every letter says, "Your son." The old man was satisfied: isn't this the real father-son relationship? The old man is warm in his heart.

But in the past two months, although the remittance still came, the letter was interrupted (the handwriting on the remittance was also very strange). The old man was anxious and intuitively felt that something unexpected must have happened.

The old man boarded the train to Yunnan with the money he saved as a bride price for his son. The head of the army took him to a place surrounded by pine trees, where two tombs of martyrs were built side by side, one for his son and the other for his "son".

1 What is the use of the quotation marks of "Xie Weimin" and "Son"?

According to the article, talk about the meaning of "Xie Weimin".