The Soldiers have to stand up for themselves and make their voices heard to the chain of command if they believe they are not being cared for properly. If they are blown off at the lowest level, they need to keep taking the issue higher. I call the battalion leadership the checkpoint. By the time you reach this level of leadership either your entire chain of command is against you (this is unlikely) or the matter you are bringing to their attention has not been properly explained, is more emotional than factual, or is the product of a person who will never be happy no matter what a leader does. In the rare case that the Soldier has a legitimate issue and they are not offered resolution at the battalion level, they can contact the IG.
What can you do from the outside?
If you, as a concerned individual, have already contacted the chain of command and given them adequate time to address the issue you can personally contact the IG or even the DOD or Army IG. If you go this route, I would caution you to ensure your comments are professional and unemotional and very specific with regard to facts. Be careful that the information you convey will not have the unintended consequence of causing problems for the Soldiers you hope to help.