What is the story of Taoist father and son? What's the point?

The Taoist father and son mainly talked about an anecdote that happened in Kyoto, the capital of the Song Dynasty (now Kaifeng, Henan). A Taoist said that he got the true story of an alchemist who could refine the elixir of life. He has been eating elixir for more than 300 years, but his face is as young as a young man in his twenties. As soon as the news spread, the dignitaries who wanted to live a long life came to the door to ask for the fairy medicine, and the door of the Taoist priest was busy for a while. One day, a Taoist priest was drinking with several senior officials in North Korea. The doorman came in and said that the Taoist priest's son had come to see him. Taoist priests are still impatient and unwilling to express their opinions. Persuaded by senior officials, he agreed to meet him. After a while, a white-haired old man came in. When he entered the room, he kowtowed to the Taoist priest and said that his father was at the scene and his son came to inquire after him. The Taoist priest told everyone that this son refused to accept Dan medicine if he didn't listen to the advice, and this has been the case until now 100 years old. Seeing this situation, all senior officials believe in the Taoist elixir. Villagers who knew the truth afterwards said that the old man was actually the father of a Taoist priest, and they co-staged a play to deceive senior officials who wanted to live a long life.

The Taoist father and son satirized the blind pursuit and unrealistic fantasy of the rich and powerful for immortality.