The OP quotes from the Old Testament, and asks about it : "If a son ceases to hear instruction, he wanders from words of knowledge.
Why would a son of a Christian family want to wander from words of knowledge?"
The Proverb discusses a Son who does not want to listen to his Parents instructing him.
This sounds like the Son is grown, and married, and is attempting to live his Life.
(Also, in OT times, the extended Family usually lives together, and is therefore, less relevant today than it was 3000 years ago.)
And there are Better words of knowledge … and Stupid words of knowledge.
Many parents will “unload” their Prejudices (and other Judgments) on their children, and expect their kids to be as BIG a Bigot as they are.
Archie Bunker lives, and is Alive-and-Well in many Families.
So, if Archie was my Dad, I would stop listening to his “instruction” … because my Dad has wandered away “from words of knowledge.”.
I doubt this Proverb is meant for everyone to think that it perfectly applies to their own Life.
When a person “Grows” as a Christian … he comes to realize what God may want him to do in his Life.
Spirituality is NOT a one-Size-fits-All endeavor.
Each person has different issues that affect their Life, and their Family.