An unworthy son is a son who does bad things. Thieves rob, rape...do things their parents wouldn't do.
An unfilial son is a son who is unfilial to his parents. Some thieves and robbers also honor their parents.
There are also people who are not filial and don’t do bad things
Now do you understand what it means? If there really is such a person, it will be hard to be good in the end... So this is called Fate Pu, I don’t know if you understand