There are many reasons why a mentor is LIFE CHANGING but I'll leave it at one very important reasons.
Your son probably isn't listening to you much, pushing back on everything you say and starting to "know it all."
Cultures for hundreds and thousands of years knew this is the time to get as many people around the young men of the village. This is the time in a young man's life where he stops listening to his parents, so you aren't alone in that.
... but who is he listening to then? I can assure you if its someone on social media - its a small % that its good, helpful and healthy advice.
Thats where I come in. You can rest assured that what I'm talking to your son about will help develop him into a well balanced young man. Heart-led and resilient.