I ask since the rank of the soldier will sometimes play into the due process they are entitled.
To answer your question, is there anything you, the others in the group or the soldier can do at this point?
Not if the board is complete and the appeals run
Under the law, a solder is entitled to "due process"before a benefit (like the on you describe) can be taken away. Due process is what is given, as a right, to the soldier in question, to challenge the decision. Due process in an administrative matter like this is almost always very limited. It is rare that a soldier actually is entitled to a hearing. If he had the hearing, and that did not go in his favor...and if he has already appealed that? That is it for due process...once the appeal is complete there is no further legal process available (for example, he can not sue to force this issue).
If they have ruled on the appeal the case is over.
That said, the beauty of an administrative process is that formal rules of procedure do not apply. So the soldier can always ask for reconsideration.
You ask what you and your group can do? This may be a spot where you can help...particularly if you have a SNCO or Officer
as part of the group
You can ask the commander (the one who made the decision to dismiss the soldier) to reconsider this.
If you have evidence that the soldier did not present on this matter, you can file a request with the commander and present that evidence.
Now...will it help?
That depends on what you have...but if you can help educate the commander about this particular soldier? It may be you can sway the commander's opinion
Now...this evidence would best be presented during the board...or during the appeal. So you are late. Way late. And it may be the commander ignores you...there is no legal reason the commander must listen now that the appeals have run. But if you have evidence about the soldier that is favorable to the soldier, AND that the commander has not heard? It may be worth the effort to contact the commander and present.
As always you want to go through the chain of command to present this, having the senior one in your group make the presentation
Please let me know if you have more questions...happy to assist if I can