Hi, My name is Philip. I am an attorney with over 16 years experience. Hopefully I can help you with your legal question.
He can try...that is, he can file a request to the "separation
authority" to withdraw his waiver of rights regarding discharge. The separation authority will be the officer
who has the authority to approve the separation. This will be the officer with general court martial convening authority
...typically the first flag officer or "admiral" in the chain of command.
But he should understand two things
1. The separation authority is not required to honor this request. That is, if your son waived his due process rights regarding separation? The separation can rely and act on that waiver and is NOT required to withdraw the waiver or to provide your son with due process rights.
2. Perhaps more important, the due process rights for a sailor facing a general discharge are limited. They are allowed to submit matters in writing to the separation authority...but no more. So even if he could withdraw his waiver, if he lost his ability to perform his job, the Navy
can separate him with a general discharge and not be required to give him a hearing. They can limit him to submitting matters in writing (for example, a written statement from himself, or statements from others)
All that said, if he wants to stay in? He can sure request it. He should put this in writing and do it soon (tomorrow would be good). He can, and should, have letters from folks who know and support him accompany his request. The separation authority will consider this request...and may well grant it.
Please let me know if you have more questions...happy to assist if I can