If the victim in a DV case shows up and does not want to press charges what happens?
1 attorney answer
Many prosecutors will decline to prosecute at that point.
Some prosecutors still want to push through a conviction under the theory that if they don't do anything, this will just happen again.
When you said "I'll go to jail" you may also have admitted to being the aggressor. But maybe you didn't. If both of you were equally at fault and equally aggressive, then you should both be charged.
If your son goes and meets in person with the prosecutor and explains the situation, the prosecutor may just drop it.
I recommend you talk to a local criminal law attorney to see what kind of prosecutor and judge you're likely to have, and if your son can get it dropped by saying he doesn't want charges.
This answer is not meant as legal advice, nor does it create an attorney client relationship between myself and the person asking the question. I am treating this as a hypothetical question, and I am giving some thoughts in response to the hypothetical based on my training and experience. The goal is to get you pointed in the right direction. The best thing for you to do, of course, is call a local attorney and schedule an appointment to get specific legal advice to your specific question.