Oh my goodness.
I would have a fit if I were you, but I'll tell you why.
I don't actually have fits, we call them conniptions.
My kids always say, "Oh no...Mom would have a conniption!"
Anyway, my grandfather chewed Copenhagen. I adored my grandfather and I thought, hey, if it's good for him, it must be good for me.
I was 8.
I snuck and tried it.
I was found passed out behind the fig tree in his backyard.
Copenhagen was not my friend.
All I remember was feeling really dizzy. And super sick to my stomach after they dragged me in the house.
Anyway, my nephew started chewing at 15.
I was absolutely shocked that my sister allowed him to do it. She even bought chew for him. He was chewing before school, during school, after school, if we went to visit he was chewing. And spitting. Yuck.
He tried to give my son some and I told him I'd rip his gonads off if he tried giving it to him again.
(I'm pretty blunt).
It's the same thing as letting your kid smoke at that age. The nicotene factor. Nicotene is highly addictive.
My nephew was, and is a good person, a good kid, but his parents let him start chewing very early thinking it was not the worst thing he coud do and they just allowed it. His dad chews so they felt it was hypocritical to tell him no.
Schools should have a zero tolerance policy for it. They don't allow smoking. You should ask.
It's not a moral thing and I love my nephew, but I certainly wish he'd never started. He talks to me about wanting to quit, but he gets nervous and edgy if he doesn't have it.
Sometimes downright mean.
One thing you might be able to get through to him with is if he is interested in girls. He's going to be 17. No girl will kiss a boy with chew mouth. I don't intend to sound mean, but I've told my nephew the same thing.
And, it may be a fad with boys, but I don't know too many girls who actually find spitting attractive either.
Definitely confront him. If you know...tell him you know. Tell him you don't like it.
You only have two choices.
Let him do it or tell him you won't stand for it.
My sister felt she was choosing her battles and let her son do it, in front of her, bought it for him.
I never would have gone that route, but he's not my kid so I didn't really have any say.
Talk to your son. Be blunt about your feelings.
I hope you get it worked out.