The stroy has traditionally been called "The Parable of the Prodigal Son." What does prodigal mean? What position does the younger son expect when he returns home to his father's house? What does the father give him? When the younger brother sees the celebration for his younger brother's return, he grows angry. He makes a very reasonable set of complaints to his father. He has indeed been a loyal and moral son, but what virtue does the older brother lack? Is the father fair to the elder son? Explain your answer. Theologians have discussed this parable's religious significance for two thousand years. What, in you own words, is the human theme of the story?

Prodigal means wasteful, extravagant, or imprudent. This is used to describe the younger brother because has behaved this way.
The prodigal son expects his father will want him to be a servant.
The older brother is envious of his brother for the attention heaped on him. He lacks empathy and compassion.
The question of the father's fairness is central to the interpretation of this story. On the one hand, it is the father's weakness that contributed to the problem: he gave in rather than hold the money for inheritance. On the other hand, the young son has free will and no one forced him to squander the money.
The question of the central message relates to point 4. It is really a matter of personal views, and may depend on the reader's personality and birth order, or position as parent or child at different life stages. Most children would probably want their parent to welcome them home with unconditional love, but many siblings would relate to the older brother's feelings.
http://famouspoetsandpoems.com/poets/rudyard_kipling/poems/14457

https://www.biblegateway.com/passage/?search=Luke+15%3A11-32