Re: 16 Year Old Marijuana Possession in Texas
I agree that this is more of an ethical question rather than a legal one. The only answer from a legal defense perspective is for your son to keep his mouth shut. From an ethical perspective, in my opinion, your son should take responsibility for his actions and accept the consequences. Go to the police and/or prosecutor and confess his culpability.
But, to answer your specific questions:
They will likely believe him. However, it is really not an issue of saving his friend. Since the weed was found in the friend's physical possession, your son claiming ownership does not exonerate the friend. Obviously, the friend was a knowing and willing participant in the possession. So, both your son and the friend will be charged with possession.
That is hard to say with any specificity. Especially since your son is a juvenile. If he has not been in trouble with the law before, he would likely be offered a diversion program. That would likely entail a period of probation, attend some drug classes (at his/your expense), and, maybe, some community service. If he successfully completes that, then the conviction would go away. Without a diversion, he would likely be sentenced to a fine, a period of probation, and keeps a juvenile drug conviction record. Either way, he will almost assuredly have his driver's license suspended.
Behind the badge is a person. Behind the person is an ego. This is as it should be, person at the center and ego to the back.