The action can range from a slap on the wrist to punishment under the UCMJ (Article 15), and in extreme cases separation from service.
The severity of the action will depend on the situation.
If your son is in basic training it could result in punishment under the UCMJ which involves potential restriction, extra duty, loss of pay, and rank.
If your son is in a permanent party unit (has completed basic training and advanced individual training) odds are if the situation is not extreme it will most likely result in some form of corrective training: writing an essay, writing a policy letter, teach a class on the subject, having the commander revoke tobacco privileges, a formal counseling statement. Worse case would be the recommendation for an Article 15 as described above.
Your son might consider:
- being accountable for his actions
- apologize for his actions
- explain that he will accept the consequences for his lapse in judgement
- give his word that he will not violate this policy at anytime in the future (learned his lesson)
Basically he is at the mercy of the NCO and the Chain of Command as to how they want to handle this situation. As I stated early it all depends on the situation. The odds of separation are almost nil, unless there has been a pattern of misconduct.